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Physics A First Course ExamView Test Bank®

Physics A First CourseExamView® Test Bank BookletCopyright 2005 CPO Science

ISBN 1-58892-156-51 2 3 4 5 6 7 8 9 - QWE - 07 06 05

All rights reserved. No part of this work may be reproduced or transmitted in any form or by anmeans, electronic or mechanical, including photocopying and recording, or by any informationstore or retrieval system, without permission in writing. For permission and other rights underthis copyright, please contact:

CPO Science26 Howley Street,

Peabody, MA 01960 (978) 532-7070

http://www.cposcience.com Printed and Bound in the United States of America

CreditsCPO Science Curriculum Development TeamAuthor: Thomas Hsu, Ph.D.Vice Presidents: Thomas Narro and Lynda PennellProject Manager: Scott EddlemanWriters: David Bliss, Mary Ann Erickson, Lainie Ives, and Mary Beth HughesGraphic Artists: Bruce Holloway, Polly Crisman, James Travers, and David Rosolko

Technical ConsultantTracy Morrow

Table of Contents

To the Teacher

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .EV-1

Test BanksNote: There are Multiple Choice and Multi-Format test banks for each chapter.

Chapter 1: Describing the Physical Universe. . . . . . . . . . . . . . . . . . . . . . 1

Chapter 2: Laws of Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Chapter 3: Conservation Laws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Chapter 4: Machines, Work, and Energy. . . . . . . . . . . . . . . . . . . . . . . . . 44

Chapter 5: Forces in Equilibrium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Chapter 6: Systems in Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Chapter 7: Temperature, Energy, and Matter . . . . . . . . . . . . . . . . . . . . . 89

Chapter 8: Physical Properties of Matter. . . . . . . . . . . . . . . . . . . . . . . . . 101

Chapter 9: The Atom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Chapter 10: Energy Flow in Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Chapter 11: Changes in Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Chapter 12: Relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

Chapter 13: Electric Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Chapter 14: Electrical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Chapter 15: Electrical Charges and Forces . . . . . . . . . . . . . . . . . . . . . . . 192

Chapter 16: Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Chapter 17: Electromagnets and Induction . . . . . . . . . . . . . . . . . . . . . . . 219

Chapter 18: Fields and Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

Chapter 19: Harmonic Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

Chapter 20: Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

Chapter 21: Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

Chapter 22: Properties of Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

Chapter 23: Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290

Chapter 24: The Physical Nature of Light . . . . . . . . . . . . . . . . . . . . . . . . 312

TO THE TEACHER The CPO Science Physics A First Course text is divided into eight units. Each unit covers specific science content and topics. The eight units are broken down into twenty-four chapters. This test builder software contains two test banks for each of the twenty-four chapters, for a total of forty-eight test banks. The first bank for each unit covers all of the important unit concepts in a multiple-choice test format. This bank will be useful for familiarizing students with the format of high-stakes standardized tests. The second bank for the same unit covers all of the important unit concepts with a variety of question types including modified true/false, completion, short answer, and essay. This test bank allows you to address a variety of learning styles within your classroom. These questions and the test generator software have been prepared to assist you in developing tests for your students. LEVELS OF DIFFICULTY Each test question is designated with one of three levels of difficulty. Questions are designated as basic, intermediate, or advanced. Basic questions test students’ knowledge and comprehension of important concepts from each unit. Intermediate questions require students to apply concepts to solve a problem. Advanced questions require students to analyze a new situation (often a scenario) using the concepts learned in the unit. Choosing questions by the level of difficulty will help you tailor your test to the needs and abilities of your students. REFERENCE Each test question is matched with the section of the student text to which it refers. You can use this information to build a section-specific quiz, or as a quick reference to locate a passage of text that teaches a particular concept or skill. COMPONENTS • CPO Science Physics A First Course Question Bank • ExamView Pro Testmaker User’s Guide • ExamView Pro Hybrid CD-ROM The CPO Science Physics A First Course test generator consists of a User’s Guide and a CD-ROM. The User’s Guide contains instructions for the setup and use of the software. It also contains a printed listing of all the questions that accompany the test generator software. Use this guide to preview the available questions and to make your choices for inclusion on tests; or, if you prefer, you may view and select questions on-screen using the included computer program. The test generator software lets you retrieve the questions you want and then print tests. It also lets you edit and add questions as needed. In the Windows version, if you have already installed the test generator program for other textbooks, you may have to select the folder named CPO Physics First to locate the question bank files that accompany the CPO Science Physics A First Course textbook.

SOFTWARE LICENSE AGREEMENT ExamView and ExamView Pro software is provided to instructors who have purchased the CPO Science Physics A First Course textbook for use in the classes they teach. The enclosed ExamView software is licensed on the condition that you have purchased and continue to use the CPO Science Physics A First Course textbook in your class and you accept all of the terms contained in the license agreement. You may install and use ExamView or ExamView Pro software on the hard disks of any number of standalone computers or on a network server for access by multiple computers provided that each instructor who accesses and uses the software has purchased and is using the CPO Science Physics A First Course textbook in his or her class. The ExamView Pro Player may be freely copied and distributed. SOFTWARE SUPPORT HOTLINE Should you have difficulty setting up or running the program, email your questions to [email protected], or call 1-862-588-6951 between 9:00 a.m. and 5:00 p.m. eastern time.

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SECTION 1 — INTRODUCTION

This user’s guide accompanies a test generator program called ExamView® Pro–an application that enables you to quickly create printed tests, Internet tests, and computer (LAN-based) tests. You can enter your own questions and customize the appearance of the tests you create. The ExamView test generator program offers many unique features. Using the QuickTest wizard, for example, you are guided step-by-step through the process of building a test. Numerous options are included that allow you to customize the content and appearance of the tests you create.

As you work with the ExamView test generator, you may use the following features: • a “wizard” to guide you through the steps to create a test in less than five minutes • five methods to select test questions

– random selection – from a list – while viewing questions – by criteria (difficulty code, objective, topic, etc.–if available) – all questions

• the capability to edit questions or to add an unlimited number of questions

• online (Internet-based) testing – create a test that students can take on the Internet using a browser – receive instant feedback via email – create online study guides with student feedback for incorrect responses

• Internet test-hosting * – instantly publish a test to the ExamView website – manage tests online – allow students to access tests from one convenient location – receive detailed reports – download results to your gradebook or spreadsheet

• online (LAN-based) testing – allow anyone or selected students to take a test on your local area network – create online study guides with student feedback for incorrect responses – incorporate multimedia links (movies and audio) – export student results to a gradebook or spreadsheet

• a sophisticated word processor – streamlined question entry with spell checker – tabs, fonts, symbols, foreign characters, and text styles – tables with borders and shading – full-featured equation editor – comprehensive graphing tool – pictures or other graphics within a question, answer, or narrative

• numerous test layout and printing options – scramble the choices in multiple choice questions – print multiple versions of the same test with corresponding answer keys – print an answer key strip for easier test grading – format the test to match a predefined format, such as a particular state test layout, with a single click

• dynamic questions (algorithms) – create dynamic questions for any subject area – algorithms allow infinite customization of a question using mathematical definitions – use built-in feature to build dynamic math content from simple addition to calculus – dynamic features are fully integrated with ExamView’s equation editor and graphing tool

• link groups of questions to common narratives * The Internet test-hosting service must be purchased separately. Visit www.examview.com to learn more.

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SECTION 2 — INSTALLATION AND STARTUP INSTRUCTIONS The ExamView test generator software is provided on a CD-ROM. The disc includes the program and all of the questions for the corresponding textbook. The ExamView Test Player, which can be used by your students to take online (computerized or LAN-based) tests, is also included.

Before you can use the test generator, you must install it on your hard drive. The system requirements, installation instructions, and startup procedures are provided below.

SYSTEM REQUIREMENTS

To use the ExamView test generator or the online test player, your computer must meet or exceed the following minimum hardware requirements:

Windows • IBM PC (or 100% compatible) computer • Pentium 120 MHz microprocessor (or higher) • Windows 98, Windows Me, Windows 2000, Windows XP (or a more recent version) • color monitor (VGA-compatible) • CD-ROM drive • hard drive with at least 10 MB space available • 16 MB available memory (32 MB memory recommended) • an Internet connection to access the Internet test-hosting features

Macintosh • PowerPC processor, 120 MHz computer • System 8.6, System 9.2, or OS X (10.2 and higher)• color monitor (VGA-compatible) • CD-ROM drive • hard drive with at least 20 MB space available • 16 MB available memory (32 MB memory recommended) • an Internet connection to access the Internet test-hosting features

INSTALLATION INSTRUCTIONS

Follow these steps to install the ExamView test generator software. The setup program will automatically install everything you need to use ExamView. Note: A separate test player setup program is also included for your convenience. [See Online (LAN-based) Testing on page 9 for more information.]

Windows Step 1 Turn on your computer. Step 2 Insert the ExamView disc into the CD-ROM drive. Step 3 Click the Start button on the Taskbar and choose the Run option.

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Step 4 Use the drive letter that corresponds to the CD-ROM drive on your computer (e.g., d:\setup.exe). The setup program, however, may be located in a subfolder on the CD-ROM if the ExamView software is included on the disc with other resources. In which case, click the Browse button in the Run dialog box to locate the setup program (e.g., d:\evpro\setup.exe). Step 5 Follow the prompts on the screen to complete the installation process. Step 6 Remove the installation disc when you finish.

Macintosh Step 1 Turn on your computer. Step 2 Insert the ExamView installation disc into your CD-ROM drive. Step 3 Open the installer window, if necessary. Step 4 Double-click the installation icon to start the program. Step 5 Follow the prompts on the screen to complete the installation process. Step 6 Remove the installation disc when you finish.

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GETTING STARTED

After you complete the installation process, follow these instructions to start the ExamView test generator software. This section also explains the options used to create a test and edit a question bank.

Startup Instructions Step 1 Turn on the computer. Step 2 Windows: Click the Start button on the Taskbar. Highlight the Programs menu and locate the ExamView Pro Test Generator folder. Select the ExamView Pro option to start the software. Macintosh: Locate and open the ExamView folder. Double-click the ExamView Pro program icon. Step 3 The first time you run the software, you will be prompted to enter your name, school/institution name, and city/state. You are now ready to begin using the ExamView software. Step 4 Each time you start ExamView, the Startup menu appears. Choose one of the options shown in Figure 1. Note: All of the figures shown in this user’s guide are taken from the Windows software. Except for a few minor differences, the Macintosh screens are identical. Step 5 Use ExamView to create a test or edit questions in a question bank.

ExamView includes three components: Test Builder, Question Bank Editor, and Test Player. The Test Builder includes options to create, edit, print, and save tests. The Question Bank Editor lets you create or edit question banks. The Test Player is a separate program that your students can use to take online (LAN-based) tests/study guides.

Figure 1 – ExamView Startup Menu Using The Help System Whenever you need assistance using ExamView, access the extensive help system. Click the Help button or choose the Help Topics option from the Help menu to access step-by-step instructions from more than 150 help topics. If you experience any difficulties while you are working with the software, you may want to review the troubleshooting tips in the user-friendly help system.

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Test Builder

The Test Builder allows you to create tests using the QuickTest Wizard, or you can create a new test on your own. (See the sample test in Figure 2.) Use the Test Builder to prepare both printed and online tests/study guides.

• If you want ExamView to select questions randomly from one or more question banks, choose the QuickTest Wizard option to create a new test. (Refer to Figure 1 on page 4.) Then, follow the step-by-step instructions to (1) enter a test title, (2) choose one or more question banks from which to select questions, and (3) identify how many questions you want on the test. The QuickTest Wizard will automatically create a new test and use the Test Builder to display the test on screen. You can print the test as is, remove questions, add new questions, or edit any question.

• If you want to create a new test on your own, choose the option to create a new test. (Refer to Figure 1 on page 4.) Then, identify a question bank from which to choose questions by using the Question Bank option in the Select menu. You may then add questions to the test by using one or more of the following selection options: Randomly, From a List, While Viewing, By Criteria, or All Questions.

Figure 2 – Sample Test

IMPORTANT: The Test Builder and the Question Bank Editor systems are integrated in one program. As you work with ExamView, you can easily switch between the Test Builder and Question Bank Editor components using the Switch to… option in the File menu.

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To create a new test: Step 1 Start the ExamView Pro software. Step 2 At the Startup window, choose the Create a new test option. Step 3 Enter a title for the new test. After you enter the title, the program will automatically display the option for you to select a question bank. Step 4 Choose a question bank. Step 5 Select the questions you want to include on the test. Use the question selection options that appear in the Select menu. Or, click the corresponding buttons on the toolbar. A description for each of the question selection toolbar buttons appears below.

Click the Question Bank toolbar button to select a question bank. You can create a test using questions from one question bank or from multiple banks.

Choose a bank, select the questions you want, and then choose another bank to select more questions.

Click the Select Randomly toolbar button when you want the program to randomly select questions for you.

Use the Select from a List command to choose questions if you know which ones you want to select. Identify the questions you want by reviewing a question bank printout.

Click the Select while Viewing button to display a window that shows all of the questions in the current question bank. Click the check boxes to select the questions you want.

You can use the Select by Criteria option to choose questions from multiple question banks based on question type, difficulty, and objective (if available).

Click the Select All button to choose all of the questions in the current question bank.

Step 6 Save the test. Step 7 Print the test. You can use the options in the Test menu to customize the appearance of a test, edit test instructions, and choose to leave space for students to write their answers. When you print a test, you may choose how many variations of the test you want, whether you want all the versions to be the same, and whether you want to scramble the questions and the multiple choice options. If you choose to scramble the questions, ExamView will print a custom answer sheet for each variation of the test. If you want your students to take a test online, first create the test. Then, publish the test as an Internet test/study guide (page 15) or use the Online Test Wizard (page 10) to create a test for delivery over a LAN (local area network). The software will walk you through the steps to turn any test into an online (Internet or LAN-based) test. IMPORTANT: You may edit questions or create new questions as you build your test. However, those questions can be used only as part of the current test. If you plan to create several new questions that you would like to use on other tests, switch to the Question Bank Editor to add the new questions.

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Question Bank Editor The Question Bank Editor allows you to edit questions in an existing publisher-supplied question bank or to create your own new question banks. Always use the Question Bank Editor if you want to change a question permanently in an existing question bank. If you want to make a change that applies only to a particular test, create a new question or edit that question in the Test Builder.

A question bank may include up to 250 questions in a variety of formats including multiple choice, true/false, modified true/false, completion, yes/no, matching, problem, essay, short answer, bimodal, case, and numeric response. You can include the following information for each question: difficulty code, reference, text objective, state objectives, topic, and notes.

Step 1 Start the ExamView Pro software. Step 2 At the Startup window as illustrated in Figure 1 on page 4, choose to Create a new question bank or Open an existing question bank. If you are working in the Test Builder, click the File menu and choose Switch to Question Bank Editor to edit or create a new question bank. Step 3 Click the New button to create a new question or click the Edit button to modify an existing question. Both of these buttons appear at the bottom of the Question Bank Editor window. (See Figure 3.)

You may add new questions or edit questions in a question bank by using the built-in word processor. The word processor includes many features commonly found in commercially available word processing applications. These features include the following: fonts, styles, tables, paragraph formatting, ruler controls, spell checking, an equation editor, tabs, indents, and justification. Step 4 Save your work. Then, exit the program or switch back to the Test Builder.

Figure 3 – Question Bank Editor

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Online Testing (LAN-based vs. Internet) The ExamView software allows you to create paper tests and online tests. The program provides two distinct online testing options: LAN-based testing and Internet testing. The option you choose depends on your particular testing needs. You can choose either option to administer online tests and study guides. The LAN-based testing option is designed to work on a local area network server. That is, you can copy the test/study guide along with the Test Player software onto your local area network. Then students can take the test at computers connected to your server. To take a LAN-based test, you must provide access for your students to the Test Player program included with the ExamView software. The Test Player is a separate program that lets your students take a test/study guide at a computer. You can store the Test Player program and the test on a local area network for easy access by your students. The Internet testing option provides a computerized testing solution for delivering tests via the Internet or an Intranet. This option is great for distance learning environments or simply to make a sample test/study guide available to students at home. Students do not need any other program (unlike the LAN-based option). When your students take a test, the results are automatically sent to you via email. You can publish an Internet test to your own website, to a publisher’s website, or you can use the ExamView Internet test-hosting service. If you subscribe to the ExamView test-hosting service, you can publish a test directly to the Internet with just a few simple steps. Students will have immediate access to the tests that you publish and you can get detailed reports. For more information on the Internet test-hosting service, visit our website at www.examview.com.

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SECTION 3 — ONLINE (LAN-BASED) TESTING Online testing features are seamlessly integrated into the ExamView software. If you want to take advantage of these capabilities, simply create a test and then use the Online Test Wizard to set up the testing parameters. Students can then take the test at the computer using the Test Player program. IMPORTANT: If you want to prepare a test/study guide for delivery via the Internet, use the Publish Internet Test option as described on page 16.

ExamView includes many features that let you customize an online (LAN-based) test. You can create a test for a specific class, or you can prepare a study guide for anyone to take. Using the Online Test Wizard, you can schedule a test or allow it to be taken anytime. As your students work on a test, ExamView will scramble the question order, provide feedback for incorrect responses, and display a timer if you selected any of these options.

ONLINE (LAN-BASED) TESTING OVERVIEW

Refer to the steps below for an overview of the online (LAN-based) testing process. Specific instructions for creating a test, taking a test, and viewing results are provided on the following pages. Step 1 Talk with your network administrator to help you set up a location (folder) on your local area network where you can install the Test Player software and copy your tests/study guides. Make sure that the administrator gives you and your students full access to the designated folders on the server. You may also want your network administrator to install the Test Player software. Step 2 Create a test/study guide, and then use the Online Test Wizard to set up the online (LAN-based) test. Save your work and exit the ExamView software. Step 3 Transfer the test/study guide file [e.g., chapter1.tst (Windows) or Chapter 1 (Macintosh)] and any accompanying multimedia files from your computer to the local area network server. Copy the files from your hard drive to the folder set up by your network administrator. You need only copy the test file unless you linked an audio or video segment to one or more questions. Step 4 Instruct your students to complete the test/study guide. Students must have access to a computer connected to the local area network on which the Test Player and test/study guide are stored. Step 5 After all students finish taking the test, copy the test/study guide file back to your hard drive. It is recommended that you copy the test to a different location from the original test file. The test file, itself, contains all of the students’ results. Note: If you set up a class roster, the test file will contain item analysis information and the results for each student. If you did not set up a roster, no results are recorded so you do not have to complete this step or the next. Step 6 Start the ExamView Pro software and open the test file to view your students’ results.

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CREATING AN ONLINE (LAN-BASED) TEST

Follow the steps shown below to create an online (LAN-based) test or study guide. Depending on the options you set, you can create a test or study guide. Before you begin, make sure that you installed the ExamView test generator and test player software. Note: See the next section (page 12) for instructions to set up the test player. (See page 15 for Internet testing features.) Step 1 Start the ExamView Pro software. Step 2 Create or open a test/study guide.

Select the questions you want to include on the test. You can include any of the following types: True/False, Multiple Choice, Yes/No, Numeric Response, Completion, and Matching. Step 3 Select the Online Test Wizard option from the Online menu.

ExamView presents step-by-step instructions to help you prepare the online test/study guide. (See Figure 4.) Read the instructions provided and complete each step. Note: Click the Help button if you need more assistance.

Figure 4 – Online Test Wizard (Step 1)

Step 4 Click the Finish button after you complete the last step using the Online Test Wizard. As you can see in Figure 5 on page 11, ExamView shows a summary that describes the settings for the online test.

Step 5 Save the test/study guide to a location where your students can easily access it. For example, save it in the same location where you installed the Test Player program.

It is recommended that you save the test/study guide to a location on a network server where students have read/write access. The Test Player will store all of your students’ results (if you entered a class roster) in the test file itself. You can copy the test to individual computers, but this configuration takes more time to gather the results.

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Figure 5 – Online Test Wizard (Summary)

Step 6 If you included multimedia links in any of the questions, copy those files to the same location where you saved the test/study guide.

If the multimedia files are on a CD-ROM or DVD disc, you may leave them on the disc, but provide this information to your students. To play one of these links, students will have to specify the location of the multimedia file. NOTES: • Use the Test Preferences and Class Roster options in the Online menu if you want to make

any changes to the test parameters. These two options let you change any of the settings you selected using the Online Test Wizard.

• You must close the test before your students can access it with the Test Player. • If you set up a class roster for a test/study guide, you cannot modify the test (e.g., edit a

question, change the order, etc.) once any student has taken it unless you clear the results first. • Provide your students with the Test Player setup program and a copy of the test/study guide if

you want them to take it at home.

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INSTALLING THE TEST PLAYER

Follow the instructions provided here to install the Test Player program for your students. You may copy the Test Player to a network (recommended), install it on individual computers, or provide it on a floppy disk for your students to take home.

Even if you have a network, you can install the Test Player on individual computers. Students will still be able to access tests/study guides you store on a local area network.

ExamView Test Player Installation Windows

Step 1 Turn on your computer. Step 2 Insert the ExamView disc into your CD-ROM drive. Step 3 Click the Start button on the Taskbar and choose the Run option. Step 4 Use the drive letter that corresponds to the CD-ROM drive (e.g., d:\evplayer\setup). Step 5 When prompted for a location to install the program, select a folder (e.g., x:\programs\evplayer for network installations or c:\evplayer on your local hard drive). Step 6 For local area network (LAN) installations, complete the following steps at each workstation: • Click the Start button and choose Taskbar from the Settings menu. • Click the Start Menu Programs tab and click Add. • Type the location and program name for the Test Player software, or use the Browse button to

enter this information (e.g., x:\programs\evplayer\evplayer.exe). • Proceed to the next screen and add a new folder (e.g., ExamView Test Player). • Enter ExamView Test Player as the shortcut name and then click the Finish button. Repeat Steps 1–5 if you plan to install the software at each computer instead of installing the program once on your network.

Macintosh Step 1 Turn on your computer. Step 2 Insert the ExamView installation disc into your CD-ROM drive. Step 3 Open the installer window, if necessary. Step 4 Double-click the installation icon to start the program. Note: The installation program is configured to copy the test player to a new folder on your hard drive. You can, however, change this location. For example, you can select a location on your network server.

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Step 5 When prompted for a location to install the program, select a folder on your local area network that is accessible to all students. If you are installing the software on a stand-alone computer, choose a location on the hard drive. Step 6 At each workstation, enable file sharing and program linking if you installed the application on your network server. For stand-alone computers, repeat Steps 1–5.

Installing the Test Player at Home You can give your students the Test Player software to take home. Copy the setup file in the evplayer folder onto a floppy disk. Students should follow Steps 1-5 to install the software on their computer. When students take a test home, they should copy it into the same folder as the Test Player program.

TAKING AN ONLINE (LAN-BASED) TEST

Make sure that you have properly installed the ExamView Test Player software and copied the test/study guide to a location easily accessible to your students. If you linked multimedia files to any of the questions, it is recommended that you copy those files to the same folder as the test/study guide.

If you created a test with a class roster, students must correctly enter their IDs to be able to take the test/study guide. Provide this information to your students, if necessary. Note: If you do not want to track student scores, you should set up a test to allow anyone to take it. Step 1 Start the ExamView Player software. Step 2 Enter your name and ID. (See Figure 6.)

Figure 6 – Online Test/Study Guide Registration

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Step 3 Select a test/study guide. (See Figure 7.)

If no tests (or study guides) appear in the list, click the Folder button to identify where the tests are located. Step 4 (Optional) Enter a password, if prompted. Step 5 Review the summary information and click Start when you are ready to begin. Step 6 Answer all of the questions and click the End button when you finish.

Verify that you want to end the test. If you do not answer all of the questions in one session, you will not be able to resume the test at a later time.

Figure 7 – Online Test/Study Guide Selection

Step 7 Review the test report. Step 8 Click New Test to take another test or click Exit to quit the program.

VIEWING ONLINE (LAN-BASED) RESULTS

If you set up a test with a class roster (instead of allowing anyone to access a test/study guide), the ExamView Test Player will automatically collect the results for each student. The program saves this information in the test/study guide file itself. Step 1 Start the ExamView Pro software and open the online test/study guide that your students have already taken. Step 2 Choose View Test Results from the Online menu. Step 3 Review the results, item-by-item analysis, and statistics reports. Step 4 Choose Export Test Results if you want to export the scores to your favorite gradebook program or spreadsheet application.

ExamView Pro EV-15

SECTION 4 — INTERNET TESTING ExamView lets you easily create Internet tests and study guides. Build a test and then simply choose the Publish Internet Test option. You can choose to post tests to your own website, to a publisher’s website (if available), or directly to the ExamView website. (Visit us at www.examview.com to learn more about subscribing to the Internet test-hosting service.) With the ExamView Internet test-hosting feature, you can publish a test or study guide directly to the ExamView website. Simply create a test and then follow the easy step-by-step instructions to publish it to the Internet. It’s that simple! You can manage tests online, view reports, and download results. Students access your tests from one convenient location. If you do not use the ExamView test-hosting service, you can manually post tests/study guides to your own website. If you create a test, your students’ results are sent to you via email automatically. Or, you can create a study guide that your students can use to review various topics at their own pace. ExamView also allows you to can also post tests directly to a publisher’s website. Contact your publisher’s sales representative to check the availability of this option.

INTERNET TESTING FAQ

Review the FAQ (frequently asked questions) below for more information on the Internet test-hosting features available to ExamView users. What are the advantages to using the Internet test-hosting feature? (1) Publishing an Internet test to your own website and setting up links can be quite challenging. With the Internet test-hosting feature, the process is completely automated. In minutes, you can post a test to the Internet. (2) When you post tests/study guides to your own website, only a few options are available. Using the ExamView test-hosting service, you have many more options available such as setting up a class roster and viewing detailed item analysis reports. How do you register for the test-hosting service? Visit our website at www.examview.com to learn how to register. Before you can post tests/study guides, you must sign up to obtain a valid instructor ID and a password. Is there an additional charge for the Internet test-hosting service? Yes, there is an additional yearly subscription charge to use this service. If you received the ExamView software from a publisher, you may be eligible for a discount or a free trial membership. (See our website for current prices and special promotions.) Do you have to use the Internet test-hosting service? No, using the test-hosting service is not required. The Publish Internet Test feature includes an option to save an Internet test/study guide to a local hard drive. Then, you can manually post it to your own website. Why aren’t the same features available for tests posted to my own website? To offer the numerous Internet test-hosting features, we have developed many programs and databases that are stored on our servers. If you post to your own server or website, these programs are not available.

IMPORTANT: Your students must use a browser such as Netscape 4.0/Internet Explorer 4.0 (or a more recent version) that supports cascading style sheets (CSS1) and JavaScript. To post tests or study guides for delivery via the Internet, you must have your own access to an Internet server.

EV-16 ExamView Pro

USING THE EXAMVIEW INTERNET TEST-HOSTING SERVICE Using the ExamView test generator software, you can publish tests directly to the ExamView website if you have signed up for the test-hosting service. With a few simple steps, you can publish tests and study guides directly to the Internet. Refer to the following instructions to register for the Internet test-hosting service, create a test, publish a test to the Internet, take tests online, manage tests, and view student results.

Register for the Internet Test-Hosting Service

Step 1 Launch your web browser and go to www.examview.com. Step 2 Go to the Instructor Center to register for the test-hosting service. Follow the instructions provided at the website to sign up. Record the instructor ID and password assigned to you. You will need this information to publish a test or study guide to the ExamView website. When you choose to publish a test, you will be prompted to enter this information. Step 3 Quit the browser.

Publish a Test/Study Guide to the ExamView Website

Step 1 Start the ExamView Pro software. Step 2 Create a new test or open an existing test.

Select the questions you want to include on the test. You can include any of the thirteen (13) question types on a test, but only the objective questions are scored. Step 3 Select the Publish Internet Test option from the File menu.

ExamView presents a window with various Internet testing options to help you prepare the online test. (See Figure 8.) Note: Click the Help button if you need more assistance.

Figure 8 – Publish Internet Test Window

ExamView Pro EV-17

Step 4 Name the test. Step 5 Select the option to publish your test to the ExamView website, and then click the Next button. Step 6 Enter your instructor ID and password. If you do not already have an instructor ID and password, click the Register Now button to launch your web browser and go to the www.examview.com website. You cannot proceed until you have a valid instructor ID and password. Step 7 Choose whether you want to publish a test or a study guide. Step 8 Specify when students may access the test/study guide. Step 9 Enter the expiration date. Step 10 Specify who should have access to this test/study guide. Anyone may take it, or you may limit access to a particular group of students. If you specify a roster, students must enter an ID and password. Step 11 Enter a student password, and click Next. Step 12 Review the summary information. Click the Back button if you need to make changes. (See Figure 9.)

Figure 9 – Publish Internet Test Window (Summary)

EV-18 ExamView Pro

Step 13 Click the Publish button when you are ready to post the test/study guide to the ExamView website. The program automatically connects to the Internet and posts the test/study guide to the ExamView server. Access the instructor options on the ExamView website (www.examview.com) to preview a test, change selected parameters, or view results. If you need to edit or delete questions, you must change the test locally and then publish a new version. Note: An Internet connection is required to publish a test/study guide. Step 14 Print a copy of the test/study guide for your records, create another test, or exit the software if you are finished.

Take a Test/Study Guide Online at www.evtestcenter.com Once you publish a test/study guide to the ExamView server, anyone in the world can access it if you provide him or her with your instructor ID and the appropriate password. (IMPORTANT: Do not give students your password, just your ID.) Provide the instructions below to your students so that they can take the test or study guide. Note: You must use a browser such as Netscape 4.0/Internet Explorer 4.0 (or a more recent version) that supports cascading style sheets level 1 (CSS1) and JavaScript. An active Internet connection is also required.

To take a test: Step 1 Start your web browser. Step 2 Go to the URL: www.evtestcenter.com. Step 3 Enter your instructor’s ID code. (See Figure 10.) Upon entering a valid instructor code, you will see a list of tests your instructor has published. Step 4 Select a test.

Figure 10 – Test Center Login (www.evtestcenter.com)

ExamView Pro EV-19

Figure 11 – Sample Internet Test

Step 5 Enter your name (if requested), student ID, and student password. Contact your instructor if you have not been assigned a student ID or you do not have a student password. Step 6 Review the test and respond to all of the questions. (See the sample test in Figure 11.) If you need help while working with a test, click the Help button shown at the bottom of the test. Click the browser's Back button to return to the test. Step 7 When you complete the test, review the entire test and then click the Grade & Submit button located at the bottom of the test. Your results will be emailed to your instructor. Depending on the test settings, you may be notified of your results immediately. To complete a study guide: Step 1 Start your web browser. Step 2 Go to the URL: www.evtestcenter.com. Step 3 Enter your instructor’s ID. You will see a list of study guides and tests your instructor has published. Step 4 Select a study guide. Step 5 Enter your name (if requested), student ID, and password. Contact your instructor if you have not been assigned a student ID or you do not have a password.

EV-20 ExamView Pro

Step 6 Review the study guide and answer all of the questions. If you need help while working with a study guide, click the Help button shown at the bottom of the screen. Click the browser's Back button to return to the study guide. Step 7 When you complete the study guide, review your responses and then click the Check Your Work button located at the bottom of the study guide. Your work is scored and you will see whether you answered each question correctly or incorrectly. No results are sent to your instructor. Step 8 Click the Reset button to erase all of your responses if you want to start over.

Review Student Results and Manage Tests When your students complete an Internet test, their results are automatically stored on the server so that you can easily access this information. If you chose to receive results via email, you will also receive the following information for each student: (1) student name and ID, (2) raw score and percentage score for objective-based questions, and (3) responses for each question (objective and open-ended questions). At the ExamView website, you may also change test-setup options, preview tests, download student results, and view your account information.

Step 1 Start your web browser. Step 2 Go to the URL: www.examview.com and access the Instructor Center. Step 3 Log in using your instructor ID and password to view the main menu options. (See Figure 12.)

Figure 12 – ExamView Website (Instructor Center)

ExamView Pro EV-21

PUBLISHING TESTS TO YOUR OWN WEBSITE If you choose not to sign up for the ExamView test-hosting service, you can still publish tests/study guides to your own website. You must save the test/study guide to your hard drive, upload the files to your website, and then provide access to your students. Refer to the following sections for step-by-step instructions.

Save an Internet Test/Study Guide to Your Hard Drive

Follow the steps shown below to create an Internet test/study guide and save it to your hard drive. Before you begin, make sure that you installed the ExamView test generator software. Step 1 Start the ExamView Pro software. Step 2 Create a new test or open an existing test.

Select the questions you want to include on the test. You can include any of the thirteen (13) question types on a test, but only the objective questions will be graded. Step 3 Select the Publish Internet Test option from the File menu.

ExamView presents a window with various Internet testing options to help you prepare the online test. (See Figure 13.) Note: Click the Help button if you need more assistance. Step 4 Name the test. Step 5 Select the option to save the test files to your local hard drive, and then click the Next button. Step 6 Choose whether you want to publish a test or a study guide. Step 7 Review the summary information. Make changes, if necessary.

Figure 13 – Publish Internet Test Window

EV-22 ExamView Pro

Step 8 Click the Save button to save the test/study guide files. When you choose to save an Internet test to your local hard drive, ExamView creates an HTML file and an accompanying folder with all of the necessary image files. This makes it easier for you to post the files to a web server. If, for example, you enter a path such as c:\examview\tests\chapter1 (Windows) or HD:ExamView:Tests:Chapter1 (Macintosh), the software will create a file called chapter1.htm and a new folder called chapter1_files with all of the required picture files. (See the illustration below.)

Step 9 Post the test/study guide to a server to make it available to your students. (See the next section for instructions for posting a test to a server.) Step 10 Once you post a test, you should verify that students can access it. You may also want to try the "Grade & Submit" feature for tests to make sure that the results are emailed to the correct address.

Note: When you create a test, ExamView encrypts the answer information so that a student cannot see the answers in the HTML page source. While this does help to prevent cheating, there is no foolproof method in an unsupervised environment.

Post a Test to Your Own Internet/Intranet Server Once you save a test/study guide formatted for the Internet, you must post all of the related files to a location on a server that your students can access. You can post the files to a local area network, Intranet server, or an Internet server. You must have an Internet connection for students to be able to submit test results. (This is not required for a study guide.) Note: Posting to a server can be a complex process. The specific steps will vary depending on the hardware and software configuration of your server. If you are not familiar with the required steps, contact your network administrator for assistance. Step 1 Start an FTP program or other utility that allows you to copy files from your hard drive to an Internet/Intranet server. Step 2 Log in to your server. Step 3 Create a new folder on your server to hold the test/study guide files. Step 4 Copy the HTML file and the accompanying folder to a location on your server that your students can access.

ExamView Pro EV-23

When you choose to save an Internet test to your hard drive, ExamView creates an HTML file and an accompanying folder with all of the necessary image files. This makes it easier for you to post the files to a web server.

IMPORTANT: By default, all of the file names are lowercase. Do not change the case since these files are referenced in the HTML document. You must copy the HTML file and the accompanying folder as is. Do not copy the HTML file into the corresponding folder. (See the illustration below.)

Step 5 Log off the server, if necessary. Step 6 Record the URL for the test/study guide HTML document or set up a link to the test.

Take a Test or Study Guide Using the Internet Once you post a test on a server, anyone in the world can access the test if you provide him or her with the Web (URL) address. Follow the instructions provided below to take a test or study guide. Note: You must use a browser such as Netscape 4.0/Internet Explorer 4.0 (or a more recent version) that supports cascading style sheets level 1 (CSS1) and JavaScript. An active Internet connection is required to submit test results.

To take a test via the Internet: Step 1 Start your web browser. Step 2 Type the web address (URL) and test name (e.g., www.school.edu/economics/test1.htm), or enter an address for a page with a link to the test. (See the sample test in Figure 14.) If the test is located on a local area network, use the open page command in the browser to open the test. Step 3 Enter your name, student ID, and email address (optional). Step 4 Answer all of the questions. If you need help while working with a test, click the Help button shown at the bottom of the test. Click the browser's Back button to return to the test. Step 5 When you complete the test, review your responses and then click the Grade & Submit button located at the bottom of the screen.

EV-24 ExamView Pro

Figure 14 – Sample Internet Test

To complete a study guide via the Internet: Step 1 Start your web browser. Step 2 Type the web address (URL) and study guide name (e.g., www.school.edu/history/study.htm), or enter an address for a page with a link to the study guide. Step 3 Enter your name. Step 4 Answer all of the questions. Step 5 When you complete the study guide, review the entire test and then click the Check Your Work button located at the bottom of the study guide. Your work is scored and you will see whether you answered each question correctly or incorrectly. No results are sent to your instructor. Step 6 Click the Reset button to erase all of your responses if you want to start over.

Receive Student Results via Email When your students complete an Internet test, the browser sends the students’ test results and all of their responses directly to you via email. The email will include the following information: • student name and ID • raw score and percentage score for objective-based questions • responses for each question (objective and open-ended questions)

Note: You will not receive any student results for Internet study guides.

ExamView Pro EV-25

USING A PUBLISHER’S TEST-HOSTING SERVICE Using the ExamView test generator software, you can publish tests directly to a publisher’s website if you have signed up for their test-hosting service. Check with your sales representative or the publisher’s website to determine if this service is offered by your publisher.

Register for the Publisher Test-Hosting Service

Before you can post a test to a publisher’s website, you must obtain an instructor ID and a password. Contact your publisher directly to register. Check with your sales representative or the publisher’s website for more details.

Publish a Test to a Publisher’s Website

Step 1 Start the ExamView Pro software. Step 2 Create a new test or open an existing test.

Select the questions you want to include on the test. You can include any of the thirteen (13) question types on a test, but only the objective questions are scored. Step 3 Select the Publish Internet Test option from the File menu.

ExamView presents a window with various Internet testing options to help you prepare the online test. Note: Click the Help button if you need more assistance. Step 4 Name the test. Step 5 Select your publisher from the Publish test to: drop-down list to publish your test to the publisher’s website, and then click the Next button. Step 6 Enter your instructor ID and password. If you do not already have an instructor ID and password, contact your publisher or sales representative. You cannot proceed until you have a valid instructor ID and password. Step 7 Review the summary information. Click the Back button if you need to make changes. Step 8 Click the Publish button when you are ready to post the test to the publisher’s website. The program automatically connects to the Internet and posts the test guide to the publisher’s server. Note: An Internet connection is required to publish a test. Step 9 Print a copy of the test for your records, create another test, or exit the software if you are finished.

1-1

Chapter 1: Describing the Physical Universe—Multiple Choice Bank

MULTIPLE CHOICE

1. All of these are very important parts of studying physics EXCEPT:a. describing the organization of the universe.b. understanding natural laws.c. memorizing complicated explanations.d. deducing and applying natural laws.

ANS: C DIF: basic REF: section 1.1

2. System variables can be observed and measured directly in a ____ scale.a. timeb. microscopicc. macroscopicd. mass


3. A carefully designed test done under controlled conditions is called a(n):a. natural law.b. experiment.c. common law.d. analysis.

ANS: B DIF: basic REF: section 1.1

4. The mass of an object is determined by:a. finding the amount of matter it contains.b. measuring its weight.c. identifying the substance from which the object is made.d. finding its dimensions.

ANS: A DIF: basic REF: section 1.1

5. A factor that affects the behavior of a system is called a(n):a. natural law.b. experiment.c. analysis.d. variable.

ANS: D DIF: basic REF: section 1.1

6. The scientific method is a process used to solve many problems. One of the first steps is:a. collecting data.b. analyzing data.c. asking a question.d. drawing a conclusion.


1-2

7. A variable that remains unchanged throughout an experiment is called the:a. control variable.b. experimental variable.c. independent variable.d. dependent variable.


8. Compared to a laboratory cart at the top of a ramp, a cart at the bottom of the ramp has:a. more energy and less stability.b. less energy and more stability.c. more energy and more stability.d. less energy and less stability.

ANS: B DIF: intermediate REF: section 1.1

9. Of the following objects, the one which has the most mass is:a. the Goodyear blimp.b. a silver dollar.c. a piece of notebook paper.d. a physics textbook.

ANS: A DIF: intermediate REF: section 1.1

10. Robin measures the force needed to pull a wagon up an incline as more weight is added. In this investigation, weight is the ____ variable.a. controlb. dependentc. independentd. natural

ANS: C DIF: intermediate REF: section 1.1

11. The unit of time used most commonly by physicists and other scientists is the:a. second.b. minute.c. hour.d. light year.


12. The independent variable on a graph can be described as the variable:a. represented on the x-axis.b. causing the change in the experimental system.c. over which a scientist has direct control when designing the experiment.d. defined by all of the statements above.


1-3

13. The conversion factor for changing one unit of length to another in the metric system is a multiple of:a. 3.b. 10.c. 12.d. 5,280.


14. Because it is based on factors of 10 and is easy to work with, scientists prefer to use the ____ system. a. metricb. Englishc. scientificd. control


15. A graph may be described as all of the following EXCEPT:a. a tool to be interpreted ONLY by trained scientists and mathematicians.b. used to describe the data collected from an experiment.c. a picture showing how two variables are related.d. easier to read than a table of numbers.


16. The length of a new pencil is closest to:a. 5 millimeters.b. 20 centimeters.c. 1.5 meters.d. 2 kilometers.


17. The number of seconds in one week is:a. 86,400.b. 604,800.c. 31,557,600.d. 3,155,760,000.


18. Which of the lists show units arranged in order from smallest to largest?a. Millimeter, centimeter, kilometer, meterb. Centimeter, meter, kilometer, millimeterc. Millimeter, centimeter, meter, kilometerd. Meter, kilometer, millimeter, centimeter


19. Which of the following lists of mass units are arranged in order from smallest to largest?a. Gigagram, microgram, kilogram, megagramb. Microgram, centigram, kilogram, gigagramc. Milligram, microgram, centigram, kilogramd. Megagram, kilogram, centigram, milligram


1-4

20. How many seconds are in a stopwatch showing 1 hour, 3 minutes, and 5 seconds?a. 68 secondsb. 245 secondsc. 7,385 secondsd. 10,805 seconds


21. A rectangular solid has dimensions of 27 millimeters × 6.8 centimeters × 0.00025 kilometers. The volume of the solid in cubic meters is ____ cubic centimeters.a. 0.0459b. 0.345c. 33.8d. 459

ANS: D DIF: advanced REF: section 1.2

22. Orlando measures the brightness of a flashlight bulb as he adds more batteries to the circuit. If he prepares a graph of the data:a. the number of batteries should be represented on the x-axis.b. the brightness of the flashlight bulb should be represented on the x-axis.c. it doesn’t matter which variable he places on the x-axis.d. he will need more information before deciding where to place the variables.

ANS: A DIF: advanced REF: section 1.2

23. On his way to a concert, John stops at the mall to buy some camera film. If you divide the distance he travels to the concert by the amount of time it took to get from his home to his concert seat, you are calculating:a. speed.b. distance.c. time interval.d. mixed units.


24. If you know the distance traveled and the amount of time it took, speed may be calculated by:a. dividing time by distance.b. multiplying time by distance.c. dividing distance by time.d. multiplying distance squared by time.


25. Of the following, which equation does NOT correctly represent a relationship between distance, time and speed?a. Distance equals speed multiplied by time.b. Speed equals time multiplied by distance.c. Time equals distance divided by speed.d. Speed equals distance divided by time.


1-5

26. The speed of a cheetah running 300 yards in 10 seconds is:a. 30 yards per second.b. 3,000 yards per minute.c. 30,000 miles per hour.d. None of the above


27. Doug rides a motorcycle at an average speed of 42 miles per hour for 3.6 hours. The distance he travels is about ____ miles.a. 11b. 38c. 47d. 150

ANS: D DIF: intermediate REF: section 1.3

28. Gwennen rides her bicycle 2.4 kilometers up a steep hill in 8 minutes. Her speed is ____ kilometers per minute.a. 0.3b. 0.6c. 3.3d. 19


29. A professional LPGA golfer walks at an average rate of 3.20 feet per second on the golf course. The amount of time required for her to walk from the tee to a green 612 feet away is:a. 0.544 minutes.b. 1.91 minutes.c. 1,958 seconds.d. 191 seconds.


30. A professional football quarterback throws a ball 32 yards down field to a receiver at a speed of 60 miles per hour. A mile equals 1,760 yards. Once the quarterback releases the ball, the football gets to the receiver in about ____ seconds.a. 1.1b. 0.53c. 0.92d. 1.9


1-6

31. Of the following, the largest unit of speed is:a. meters per second.b. kilometers per hour.c. miles per hour.d. inches per second.

ANS: A1 meter per second = 2.24 miles per hour , 3.60 kilometers per hour, 39.4 inches per secondThese values may be calculated by the student using conversion factors discussed in classe.g. 1 hour = 3600 seconds, 1 mile = 1.61 kilometers, 1 meter = 39.4 inches

DIF: advanced REF: section 1.3

32. The speed of a car traveling 200 meters in 10 seconds is equivalent to:a. 20 yards per second.b. 2000 meters per second.c. 72 kilometers per hour.d. 115 miles per hour.

ANS: C DIF: advanced REF: section 1.3

1-7

Chapter 1: Describing the Physical Universe—Multi-format Bank

MODIFIED TRUE/FALSE

1. Matter is exchanged any time something gets hotter, colder, faster, slower, or changes in any other observable way. ________________________

ANS: F, Energy DIF: basic REF: section 1.1

2. Control variables are those that are changed in an experiment to test some aspect of a physical system. ________________________

ANS: F, Experimental DIF: basic REF: section 1.1

3. Generally, as more energy is added to a system it becomes less stable. ________________________

ANS: T DIF: basic REF: section 1.1

4. The distance an object travels may be calculated by dividing the speed of an object by the time of travel. ________________________

ANS: F, multiplying DIF: intermediate REF: section 1.3

COMPLETION

1. A set of rules that is based upon recurring facts or events that have been carefully documented is called a ____________________ (two words).

ANS: natural law DIF: basic REF: section 1.1

2. The detailed explanation of the results of an experiment is called the ____________________.

ANS: analysis DIF: basic REF: section 1.1

3. A factor affecting the behavior of a system is referred to as a ____________________.

ANS: variable DIF: basic REF: section 1.1

4. In an experiment, an educated guess that predicts the relationship between the independent and dependent variables is called the ____________________.

ANS: hypothesis DIF: basic REF: section 1.1

5. The ability of one system to cause change in other systems is known as ____________________.

ANS: energy DIF: basic REF: section 1.1

1-8

6. The two most common systems of standardized units for expressing measurements are the ____________________ system and the ____________________ system.

ANS: English, metricmetric, EnglishEnglish, InternationalInternational, EnglishSI, EnglishEnglish, SI

DIF: basic REF: section 1.2

7. A picture that shows how two variables are related is called a ____________________.

ANS: graph DIF: basic REF: section 1.2

8. On a graph, the independent variable is represented on the ____________________-axis.

ANS: xhorizontal


9. The amount of distance traveled in a given amount of time measures ____________________.

ANS: speedvelocity


10. The word meaning “for every” or “for each” is ____________________.

ANS: per DIF: basic REF: section 1.3

SHORT ANSWER

1. List three fundamental activities involved in the study of physics.

ANS: The study of physics should include the following:1. Describing the organization of the universe.2. Understanding natural laws.3. Deducing and applying natural laws.


1-9

2. Summarize the method for solving physics problems by listing the steps in the four-step technique:

ANS: 1. Clearly identify the problem to be solved.2. Identify the information given.3. Identify relationships involving the information given.4. Combine the relationships with the information given to solve the problem.


3. What two measurements do you need to know in order to determine the speed of something?

ANS: distance and time


PROBLEM

1. Calculate the number of millimeters in 2.13 kilometers.

ANS:

2.13 kilometers ×1,000 meters1 kilometer

×1000 millimeters

1 meter= 2,130,000 millimeters, or 2.13× 106 millimeters

DIF: intermediate REF: section 1.2

2. How many centimeters tall is a person who is 1.65 meters tall?

ANS:

1.65 meters ×100 centimeters

1 meter= 165 centimeters


3. Convert the following quantity of time to seconds.3:45:12

ANS:

3 hours ×3600 seconds

1 hour

Ê

Ë

ÁÁÁÁÁÁÁ

ˆ

¯

˜˜˜+ 45 minutes ×

60 seconds1 minute

Ê

Ë

ÁÁÁÁÁÁÁ

ˆ

¯

˜˜˜+ 12 seconds

= 10,800 seconds + 2,700 seconds + 12 seconds

= 13,512 seconds


1-10

4. A Canada goose flies 150 kilometers in 2.2 hours. What is the speed of the goose?

ANS: 68 kph

speed =distance

time=

150 kilometers2.2 hours

= 68kilometers

hour


5. Arnold the astronaut sends a laser signal from his moon base headquarters to Earth. If the signal, traveling at 186,000 miles per second (the speed of light), is received on Earth 1.280 seconds after it is sent, what is the distance between Arnold’s lunar headquarters and Earth?

ANS: distance = speed × time

distance (moon to Earth) =186,000 miles

second× 1.280 seconds = 238,000 miles


6. Emma walks to school at a speed of 3 miles per hour. If it takes her 20 minutes to walk from home to school, how many miles away is the school from her house?

ANS:

20 minutes ×1 hour

60 minutes= 0.33 hours

distance = speed × time =3 mileshour

× 0.33 hours = 1 mile


7. If Lynda can run 2 miles in 15 minutes, what is her speed in miles per hour?

ANS:

First, convert minutes to hours: 15 min ×1 hour60 min

= 0.25 hours

time = 0.25 hours; distance = 2 miles

speed =distance

time=

2 miles0.25 hours

= 8 miles per hour


1-11

8. A professional bicyclist rides a time trial in which he travels at 51.2 kilometers per hour for 55 minutes. How far does he travel?

ANS:

distance = speed × time = 51.2kilometers

hour× 55 minutes ×

1 hour60 minutes

= 46.9 kilometers


9. Recently, the speed limit between Utica and Rome, New York was raised from 55 miles per hour to 65 miles per hour. If the distance from Utica to Rome is 12 miles, how many minutes are saved by traveling at the new speed limit?

ANS:

time =distancespeed

old time (Utica to Rome) =12 miles

55 miles per hour

= 0.218 hour ×60 minutes

1 hour

= 13.1 minutes

new time (Utica to Rome) =12 miles

65 miles per hour

= 0.185 hour ×60 minutes

1 hour

= 11.1 minutes

time savings = 13.1 minutes − 11.1 minutes

= 2 minutes


ESSAY

1. A child’s wagon rolls from the top of a hill to the bottom of a hill. Discuss the changes in energy and the stability of the system of the wagon and the hill as a result of these energy changes.

ANS: At the top of the hill, the wagon has more energy and is less stable. At the bottom of the hill, the wagon has less energy and is more stable.


1-12

2. Tell why it is important to include units whenever you describe a measurement.

ANS: All measurements must include units in order for the measurement to be understood. All measurements are made by comparing one quantity with another. If a measurement is given only as a number it is impossible to tell which quantity is being used for comparison.Therefore, the size of the quantity which is being described cannot be determined.


2-13

Chapter 2: The Laws of Motion—Multiple Choice Bank

MULTIPLE CHOICE

1. The inertia of an object is related to its:a. mass and speed.b. mass and force.c. mass only.d. speed only.


2. Newton's first law is also known as the law of:a. inertia.b. universal gravitation.c. force pairs.d. unbalanced forces.


3. If the net force acting on a moving object is zero, the object will:a. slow down and, eventually, stop.b. continue at the same speed but change direction.c. continue in the same direction but change speed.d. continue in the same direction with no change of speed.


4. A ball with a mass of 1 kilogram is moving in a straight line at the same speed as a ball with a mass of 10 kilograms. Both balls are brought to rest in 4.0 seconds. What is true of the force required to stop the balls?a. It takes less force to stop the 1 kilogram ball because it has less inertia.b. It takes more force to stop the 1 kilogram ball because it has more inertia.c. It takes the same force to stop both balls because they moving at the same speed.d. It takes less force to stop the 10 kilogram ball because it has less inertia.


5. If an object is accelerated, all of the following may occur EXCEPT:a. a change of speed.b. a change of direction.c. it remains motionless.d. a change of direction and speed.


6. The newton is defined as the:a. force of gravity acting on a one kilogram object at Earth’s surface.b. force that can give a 1-kilogram mass an acceleration of 1 m/sec2.c. speed of an object when under the influence of Earth’s gravitational field.d. mass of an object that is accelerated at a rate of 1 m/sec2.


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7. All of the following examples of motion can be caused by a force EXCEPT a:a. car moving around a corner at 30 miles per hour.b. boat speeding down a lake at 100 kilometers per hour.c. skateboarder rolling to a stop.d. motorcycle accelerating from 0 to 70 miles per hour in 4.2 seconds.


8. The equation that correctly expresses Newton’s second law is:a. force = mass ÷ acceleration.b. force = mass × acceleration.c. force = mass + acceleration.d. force = mass - acceleration.


9. The term that best describes the motion of an object that is slowing down is:a. free fall.b. gravity.c. deceleration.d. uniform.


10. Units of measurement used to label a quantity of acceleration are:a. cm2/sec.b. sec2/cm.c. cm/sec.d. cm/sec2.


11. The rate of change in the speed of an object is known as:a. velocity.b. displacement.c. acceleration.d. equilibrium.


12. Acceleration of an object must be caused by a force that is:a. positive.b. zero.c. negative.d. not zero.


13. The metric unit of force preferred by scientists is the:a. kilogram.b. newton.c. mima.d. pound.


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14. Toby glances at the speedometer on his bicycle as he begins to roll downhill. It indicates he is traveling at 12 miles per hour when he initially looks at it and 20 miles per hour 4 seconds later. His acceleration is:a. 2 mph/sec.b. 3 mph/sec.c. 5 mph/sec.d. 8 mph/sec.


15. The inertia of two objects must be the same if:a. the acceleration of both objects is the same.b. the same force causes the same acceleration in both objects.c. the product of their mass and speed are the same.d. both objects are moving at the same speed in the same direction.

ANS: B DIF: advanced REF: section 2.2

16. A ball with a mass of 1 kilogram is moving in a straight line at the same speed as a ball with a mass of 10 kilograms. What must be true of the force required to stop the balls?a. It takes the same force to stop both balls because they are moving at the same speed.b. It takes more force to stop the 10 kilogram ball because it has more inertia.c. It takes more force to stop the 1 kilogram ball because it has more inertia.d. The forces required to stop the balls cannot be determined from the information given.

ANS: DSince the rate of negative acceleration is not known, the amount of force to cause that acceleration cannot be calculated. If the rates of deceleration were the same, the 1-kilogram ball would be stopped sooner because it has less mass (and less inertia)


17. Two forces are applied to a 2.0-kilogram block on a frictionless, horizontal surface, as shown in the following diagram:

The acceleration of the block is:a. 3.0 m/sec2 to the right.b. 3.0 m/sec2 to the left.c. 5.0 m/sec2 to the right.d. 5.0 m/sec2 to the left.


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18. A series of forces was applied to each of two blocks, A and B. The graphs below show the relationship between the force and the acceleration for each block.

Compared to the mass of block A, the mass of block B is:

a. the same.b. twice as great.c. half as great.d. four times as great.


19. When an object is accelerating due to the force of gravity with no other forces acting on it, it is:a. changing direction.b. motionless.c. in free fall.d. at terminal speed.


20. The acceleration due to gravity is:a. 9.8 m/sec2 on Earth.b. signified by the letter g.c. a downward acceleration.d. All of the above


21. When you throw a ball up in the air, it travels up and then stops instantaneously before falling back down. At the point where it stops and changes direction to fall back down its:a. acceleration is zero.b. velocity is zero.c. force is zero.d. mass is zero.


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22. A bungee jumper falls off a tower and travels 2 seconds before the bungee cord starts to slow her down. What was her average velocity in free fall?a. 4.9 m/secb. 9.8 m/secc. 14.5 m/secd. 19.6 m/sec


23. A ball is dropped off the roof of a tall building. If the ball reaches the ground in 3 seconds, how tall is the building?a. 9.8 metersb. 14.7 metersc. 29.4 metersd. 44.1 meters


24. Terminal speed occurs when:a. the air resistance of an object increases.b. an object starts to slow down due to air resistance.c. the force of gravity is balanced by the air resistance of an object.d. the acceleration due to gravity equals zero.


25. An object is dropped from rest and falls downward for 3 seconds. What is its average speed?a. 1.6 m/secb. 9.8 m/secc. 14.7 m/secd. 29.4 m/sec


26. A skydiver reaches an instantaneous velocity of 88.2 meters per second before opening his parachute. How long was he in free fall?a. 4.5 secondsb. 8 secondsc. 9 secondsd. 864 seconds


27. The slope of a position versus time graph represents:a. acceleration.b. force.c. position.d. speed.


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28. If the x-axis of a graph has a value of zero, the area enclosed between the best-fit line and the horizontal axis of a speed versus time graph represents:a. acceleration.b. distance.c. position.d. speed.


29. The slope of a speed versus time graph represents:a. acceleration.b. distance.c. force.d. velocity.


30. The slope of the line of a graph is calculated by:a. dividing the change in the horizontal values by the change in the vertical values.b. multiplying the change in the horizontal values by the change in the vertical values.c. dividing the change in the vertical values by the change in the horizontal values.d. multiplying the change in the vertical values by the change in the horizontal values.


31. The graph below represents the motion of a moving vehicle. What is the speed of the vehicle during the time interval from t = 2.0 seconds to t = 4.0 seconds?

a. 0.0 m/secb. 5.0 m/secc. 7.5 m/secd. 10. m/sec


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The graph below represents the speed-time relationship for a 2.0-kilogram mass moving along a horizontal frictionless surface:

Figure 2-1A

32. According to Figure 2-1A, what is the speed of the 2.0-kilogram mass when the time equals 5 seconds?a. 1 m/secb. 2 m/secc. 3 m/secd. 4 m/sec


33. According to Figure 2-1A, during which interval is no net force being applied to the object?a. A to Bb. B to Cc. C to Dd. E to F


34. According to Figure 2-1A, during which interval is the object accelerating at the greatest rate?a. A to Bb. B to Cc. C to Dd. E to F


35. According to Figure 2-1A, during which time interval is the acceleration of the object zero?a. A to Bb. C to Dc. D to Ed. E to F


36. According to Figure 2-1A, what is the acceleration of the 2.0-kilogram mass during interval from C to D?a. increasing at 1.0 m/sec2

b. decreasing at 1.0 m/sec2

c. increasing at 2.0 m/sec2

d. decreasing at 2.0 m/sec2


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37. According to Figure 2-1A, what distance does the mass move during interval A-D?a. 12 metersb. 18 metersc. 20 metersd. 24 meters


38. Which two graphs represent the motion of an object on which the net force is zero?

a. 1b. 2c. 3d. 4


39. Which pair of graphs represents the same motion?

a. Ab. Bc. Cd. D


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Chapter 2: The Laws of Motion—Multi-format Bank

MODIFIED TRUE/FALSE

1. Force is the ability to change motion. _________________________


2. Newton’s second law is often called the law of inertia. _________________________

ANS: F, first DIF: basic REF: section 2.1

3. The acceleration of an object is equal to the force multiplied by the mass. _________________________

ANS: F, divided DIF: basic REF: section 2.2

4. The rate of change of the distance of an object is called its acceleration. _________________________

ANS: Fspeedvelocity


5. The area under the line of a speed versus time graph represents the distance traveled by a moving object. _________________________


COMPLETION

1. The motion of an object will continue in the same direction at the same speed unless the object is acted upon by a ____________________.

ANS: force DIF: basic REF: section 2.1

2. The amount of matter an object has is called its ____________________.

ANS: mass DIF: basic REF: section 2.1

3. The mass of a body is the only property of that body that determines its ____________________.

ANS: inertia DIF: intermediate REF: section 2.1

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4. The metric unit most often used by scientists to measure force is the ____________________.

ANS: newtonN


5. The amount of change in the speed of an object divided by the amount of time it took to change the speed represents ____________________.

ANS: acceleration DIF: basic REF: section 2.2

6. An object accelerating toward Earth under only the influence of the force of gravity is said to be in ____________________ (two words).

ANS: free fall DIF: basic REF: section 2.3

7. The ratio of the “rise” (vertical change) to the “run” (horizontal change) of the best-fit line on a graph represents the ____________________ of the graph.

ANS: slope DIF: basic REF: section 2.4

SHORT ANSWER

You are a passenger sitting in the right side of a traveling car. The driver swerves to the left to avoid hitting a deer in the road. Answer the following questions about the motion you experience.

1. What motion would you experience as the passenger in the car?

ANS: You would feel as if you were being “thrown” against the right side of the car.


2. Using Newton’s first law, explain the your motion as a passenger in the right side of the car.

ANS: Answers will vary. Examples include:You are traveling in a straight line and continue to travel in a straight line due to your inertia even after the car swerves to the left.


3. Using Newton’s second law, explain the your motion as a passenger in the right side of the car.

ANS: Answers will vary. Examples include:Since the door of the car is swerving with the rest of the car, you are being accelerated to the left by the door of the car on the right and feel the force of the door acting on your body.


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4. Describe two ways in which the motion of a body could be changed to cause it to accelerate. Give an example of each.

ANS: Answers will vary. Examples include:Changes in speed and /or direction represent acceleration of a body. Applying the brakes to slow a car or stepping on the gas pedal to increase the speed of the car would cause negative acceleration (deceleration) or positive acceleration. Turning the steering wheel would cause a change in direction, also acceleration. Turning on a snowboard as you slow to a stop would represent a change in direction and speed, both examples of acceleration.


5. Describe the difference between a positive and a negative acceleration.

ANS: An object with a positive acceleration is speeding up and an object with a negative acceleration is slowing down.


6. When you throw a ball up in the air, it travels up and then stops instantaneously before falling back down. Describe its velocity and acceleration at the point where it stops and changes direction to fall back down.

ANS: Its velocity is zero and its acceleration remains -9.8 m/sec2.


7. When you drop a sheet of crumpled paper and a sheet of flat paper off a table at the same time, why does the flat sheet of paper hit the ground later?

ANS: Because of its shape, the flat sheet of paper has more force due to air resistance than the crumpled paper. Because the air resistance on the flat sheet of paper is more, the net force down (equal to force due to gravity minus force due to air resistance) is lower, causing it to accelerate more slowly than the flat sheet and reach the ground later.


8. How can the distance a sprinter has run be determined from a graph of the sprinters’s speed versus time? Assume the x-axis represents zero speed.

ANS: By finding the area under the best-fit line of the graph.


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9. The motion of a car is represented by a speed versus time graph. The line of the graph slopes down from left to right. What is the car doing?

ANS: Decelerating or negatively accelerating or slowing down.


PROBLEM

1. Tom pushes on a 50-kilogram box with a force of 25 newtons. Assuming the surface on which the box moves is frictionless, at what rate does the box accelerate?

ANS: force = mass × acceleration

acceleration =forcemass

=25 newtons50 kilograms

acceleration = 0.5 N/kg or 0.5 m/sec2


2. Two body builders are involved in a weight lifting contest to determine who is the stronger. Ivan lifts 480 pounds. Igor lifts 2000 newtons. Who is stronger?

ANS: Ivan is stronger; 480 pounds is equal to 2150 newtons, which is larger than Igor’s 2000 newtons.480 pounds × 4.48 newtons/pounds = 2150 newtons


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3. In the graph below, the acceleration of an object is plotted against the net force on the object. What is the mass of the object?

ANS: 2 kilogramsThe mass of the object is the ratio of the change of the acceleration to the change of the net force, which is the slope of the graph. The slope of the graph (and the mass) is 2 m/sec2 per newton or 2 kilograms.


4. An acorn falls from the top of an oak tree. If it takes 2 seconds for the acorn to fall, how tall is the tree?

ANS: 19.6 metersvf = g × time = 9.8 m/sec2Ê

ËÁÁÁ

ˆ¯˜ 2 sec( ) = 19.6 m/sec

vavg =vi + vf

2=

0 + 19.6 m/sec2

= 9.8 m/sec

distance = vavg × time = 9.8 m/sec( ) 2 sec( ) = 19.6 meters


5. What is the average speed of a ball thrown downward with an initial speed of 4.9 m/sec that falls for 0.5 seconds? How far does the ball fall?

ANS: vf = g × time = (9.8 m/sec2)(0.5 sec) = 4.9 m/sec

vavg =vi + vf

2=

4.9 m/sec + 4.9 m/sec2

= 4.9 m/sec

distance = vavg × time = 4.9 m/sec( ) 0.5 sec( ) = 2.45 meters


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6. To support a mass of 1.0 kilogram on Earth requires a force of ____________________ pounds.

ANS: 2.2 poundsforce = mass × acceleration

force = 1.0 kg× 9.8 m/sec2 = 9.8 N

1 lb = 4.48 N; 1 N = 0.223 lbs

force = 9.8 N × 0.223lbsN

force = 2.2 pounds


7. What is the weight in newtons of a 15-kilogram toddler on Earth?

ANS: weight = mass × g = (15 kg)(9.8 m/sec2 )

weight = 147 newtons


8. Use the graph representing the distance versus time for a car moving in a straight line to find the speed of the car from time = 2.0 seconds to time = 4.0 seconds.

ANS: 10 m/s

Speed = the slope of the graph from t = 2 sec to t = 4 sec

slope =∆x∆y

=30 m− 10 m4 sec − 2 sec

=20 m2 sec

slope = 10 m/sec


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9. Below is a graph representing the distance versus time for an object moving in a straight line. Identify the interval during which the car is not moving.

ANS: The speed is zero from time = 2.0 seconds to time = 4.0 seconds.The slope of the best-fit line of a distance versus time graph represents the speed. Speed is zero when the slope is zero. The slope is zero from t =2 seconds to t = 4 seconds.


The graph below represents the speed-time relationship for a 2.0-kilogram mass moving along a horizontal frictionless surface.

Figure 2-1

10. According to Figure 2-1, how far does the object move from time = 0 seconds to time = 6 seconds?

ANS: 20 metersThe distance traveled equals the area under the graph for the time interval in question.The area under the graph for 0 seconds to 1 seconds = 2 meters, for 1 seconds to 4 seconds = 12 meters, for 4 seconds to 6 seconds = 6 metersfor a total of 20 meters.


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11. Use Figure 2-1 to identify the intervals during which the mass is increasing in speed, decreasing in speed, and moving with constant speed.

ANS: Increasing in speed: 0 seconds to 1 second;Decreasing in speed: 4 seconds to 6 seconds; and 8 seconds to 11 secondsMoving with constant speed: 1 seconds to 4 seconds; and 6 seconds to 8 seconds.


12. Use Figure 2-1 to calculate the force applied to the object during the first second.

ANS: 8 newtons

The acceleration is the slope of the line between 0 seconds and 1 second.acceleration = 4 m/sec2

force = mass × acceleration

force = 2.0 kg × 4 m/sec2

force = 8 newtons

DIF: advanced REF: section 2.2, section 2.4

ESSAY

1. Explain the difference between the mass and the weight of an object.

ANS: Mass is the measure of the amount of matter in an object. It measures the inertia of a body, that is, its reluctance to respond to a net force. Weight is the measure of the force due to gravity on the mass of an object. The inertia and mass of an object will not change by moving it to another gravitational system, but its weight will change.

DIF: intermediate REF: section 2.1, section 2.2

2. The law of inertia states that no force is required to maintain the motion of a moving object. Explain why you must continue to pedal your bicycle even on a level surface to keep it moving.

ANS: An object in motion will remain in motion as long as there is no net force acting on the object. While you pedal your bicycle, there is the net force of friction acting upon the bicycle. To keep the bicycle moving, you must apply a force to balance the force of friction so that the net force on the moving bicycle will be zero while the bicycle is in motion.


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Chapter 3: The Conservation Laws—Multiple Choice Bank

MULTIPLE CHOICE

1. As the speed of a rolling ball is increasing, the increasing speed is accompanied by:a. increasing momentum.b. increasing inertia.c. decreasing momentum.d. both increasing inertia and momentum.


2. “Forces occur in pairs” is another way of stating Newton’s:a. first law of motion.b. second law of motion.c. third law of motion.d. universal law of motion.


3. Even though every action force has an equal but opposite reaction force, they do not cancel one another and motion may still occur because the:a. action and reaction forces are applied to the same object.b. action and reaction forces are applied to different objects.c. two forces have different magnitudes.d. two forces have equal magnitudes.


4. To calculate momentum:a. add the mass of an object to its inertia.b. add the mass of an object to its velocity.c. multiply the mass of an object by its inertiad. multiply the mass of an object by its velocity.


5. The impulse applied to an object is equal to the change in the object’s:a. mass.b. inertia.c. momentum.d. height.


6. To increase the final momentum of a racquetball, the player should:a. swing the racquet as fast as possible.b. follow through when hitting the ball.c. increase contact time with the ball.d. All of the above


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7. The impulse necessary to change the momentum of a 20-kilogram object by 5 kg·m/sec is:a. 4 kg·m/sec.b. 5 kg·m/sec.c. 15 kg·m/sec.d. 100 kg·m/sec.


8. A rocket can fly into space because:a. the exhaust gases push against the ground and the ground, in turn, pushes the rocket.b. the rocket pushes on exhaust gases and the exhaust gases push back on the rocket.c. as the fuel burns, the rocket’s mass decreases reducing the force of gravity on the rocket.d. the launch pad absorbs momentum that it imparts to the rocket.


9. The momentum of a 2000 kilogram car traveling at 20 meters per second is:a. 0 kg·m/sec.b. 0.001 kg·m/sec.c. 100 kg·m/sec.d. 40,000 kg·m/sec.


10. If a 40,000 kilogram rocket were traveling from its launch pad at a speed of 150 meters per second, 800 kilograms of gases would be expelled from the rocket at a speed of about:a. 0.33 m/sec.b. 270 m/sec.c. 7,500 m/sec.d. 21,000 m/sec.


11. Air bags reduce injury in automobile accidents by:a. reducing the time of collision.b. reducing the change in momentum.c. increasing the applied force.d. increasing the time of collision.


12. Ken rolls a 7-kilogram bowling ball so slowly that it stops before it moves through all of the pins. The impulse necessary to stop this bowling ball rolling at 2 meters per second is ____ newton-seconds.a. 3.5b. 5.0c. 7.0d. 14


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13. Kiki accidentally nudges a glass tumbler with her elbow and it falls toward a hard, ceramic tile floor. As a soccer player, Kiki reacts by catching the glass with her foot and lowering it to the floor, preventing the glass from breaking. Her action prevents the breakage because:a. the change in momentum is smaller when Kiki catches and lowers the glass to the floor.b. the impulse is smaller when Kiki catches the glass and lowers it to the floor.c. the time interval for stopping is greater when Kiki catches the glass with her foot.d. a larger force is exerted by Kiki’s foot to stop the glass in time.


14. While standing on a stationary skateboard, Jolene tosses a heavy ball horizontally toward one end of her skateboard. The skateboard moves. Assuming there is no friction in the system when the ball is tossed, which statement about the momentum of the heavy ball is INCORRECT?a. The ball’s momentum is equal in size to the momentum of Jolene and her skateboard.b. The ball’s momentum plus the momentum of Jolene and her skateboard equals zero.c. The ball’s momentum has increased because Jolene has tossed it.d. The directions of the ball’s momentum and Jolene’s momentum are the same.


15. Alex hits a line drive directly up the middle which leaves his bat traveling at 250 meters per second. If the pitcher has thrown the 0.15-kilogram baseball to Alex at 140 meters per second, what is the impulse applied to the baseball by Alex?a. 17 newton-secondsb. 21 newton-secondsc. 38 newton-secondsd. 59 newton-seconds


16. A 0.15-kilogram baseball thrown at a speed of 50 meters per second and a 7.25-kilogram bowling ball rolling at 2 meters per second are both stopped in 0.2 seconds.a. The baseball is stopped with less force because it has less inertia.b. The baseball is stopped with less force because it has less momentum.c. The bowling ball is stopped with less force because it has less momentum.d. The bowling ball is stopped with less force because it has less inertia.


17. What impulse must be applied to a 3-kilogram object to give it 150 joules of kinetic energy?a. 21 newton-secondsb. 30 newton-secondsc. 50 newton-secondsd. 3,000 newton-seconds


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18. The skateboard on which you are standing moves as one of your feet pushes on the ground because the force you apply on the skateboard:a. equals the force applied to you by the skateboard.b. is larger than the force applied to you by the skateboard.c. equals the force applied by the ground on the skateboard.d. is larger than the force applied by the ground on the skateboard.


19. Jumping on a trampoline, Jeffrey can easily soar 6 feet into the air but can only jump 2 feet from the blacktop of the driveway basketball court because the:a. court applies a larger impulse.b. trampoline applies a larger impulse.c. court applies less force on Jeffrey.d. trampoline applies more force on Jeffrey.


20. Energy that is stored due to the position of an object may be called ____ energy.a. kineticb. potentialc. radiantd. nuclear


21. A 20-kilogram object falls 2.0 meters to the floor. At what point in its fall does the kinetic energy of a body equal its potential energy?a. At all points of the fallb. Very nearly at the top of the fallc. Halfway to the floord. Just the instant before it hits the floor


22. An object falls without friction near Earth’s surface. The loss of its potential energy is equal to its:a. loss of height.b. loss of mass.c. gain in kinetic energy.d. gain in velocity.


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23. The diagram below represents a cart traveling from left to right along a frictionless surface with an initial speed of 3 m/sec. At what point is the potential energy least?

a. Ab. Bc. Cd. D


24. The ability to cause change is defined as:a. force and is measured in newtons.b. power and is measured in watts.c. energy and is measured in joules.d. impulse and is measured in newton-seconds.


25. Work may be measured using units of:a. watts.b. newtons.c. joules.d. newtons per second.


26. In science, work is defined as:a. the mass of an object multiplied by its acceleration.b. the mass of an object multiplied by the force required to move it.c. force multiplied by the distance moved in a direction perpendicular to the force.d. force multiplied by the distance moved in the same direction as the force.


27. Potential energy increases as a marble:a. slows rolling up an incline.b. increases speed down an incline.c. rolls at uniform speed on a level table.d. sits motionless on the floor.


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28. Calculate the work done to lift a barbell weighing 100 newtons a distance of 1.5 meters.a. 0.015 joulesb. 15 joulesc. 66.7 joulesd. 150 joules


29. Jonah is pushing his younger sister, Jessica, on a swing. If Jessica weighs 350 newtons, how much higher above the ground must Jonah push her to increase her potential energy by 525 joules?a. 0.67 metersb. 1.5 metersc. 3.6 metersd. 5.4 meters


30. A basketball player who weighs 600 newtons jumps 0.5 meters vertically off the floor.What is her kinetic energy the instant before hitting the floor?a. 30 joulesb. 60 joulesc. 300 joulesd. 600 joules


31. Lifting a 70-kilogram barbell 2.0 meters above the floor increases its potential energy by about:a. 35 joules.b. 140 joules.c. 350 joules.d. 1,400 joules.


32. The amount of mechanical kinetic energy possessed by a 0.25-kilogram ball rolling at a speed of 2.5 meters per second is ____ joules.a. 0.31b. 0.63c. 0.78d. 1.6


33. As the speed of a moving object doubles, the amount of mechanical kinetic energy that it possesses:a. increases by two times.b. increases by four times.c. decreases by two times.d. decreases by four times.


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34. Jonah is pushing his younger sister, Jessica, on a swing. If Jessica weighs 35 kilograms, how much higher above the ground must Jonah push her to increase her potential energy by 525 joules?a. 0.67 metersb. 1.5 metersc. 3.6 metersd. 5.4 meters


35. Shawna, who weighs 54 kilograms, is roller blading on a level surface. If she is rolling at 12 meters per second, to what height would she roll up an incline before stopping? (Assume there is no friction.)a. 0.61 metersb. 1.2 metersc. 7.3 metersd. 15 meters


36. When the brakes are fully applied, compared to the distance required to stop a car going 30 miles per hour, the distance needed to stop a car going 90 miles per hour is:a. 3 times as great.b. 6 times as great.c. 9 times as great.d. the same.


37. All of the following may be the result of an inelastic collision EXCEPT:a. permanent change in the shape of the colliding bodies.b. kinetic energy released as sound.c. colliding bodies stick to one another.d. zero loss of kinetic energy.


38. Which of the following situations is an example of a mostly elastic collision?a. Two billiard balls collide and bounce off each other.b. Two train card collide and stick together.c. When a soft piece of clay falls onto the floor, its shape flattens.d. A glass falls off the table and breaks.


39. When two objects hit each other, a(n) ____ occurs.a. jouleb. impulsec. collisiond. momentum


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40. A boy whose mass is 40 kilograms runs at 5 meters per second and jumps onto a 10-kilogram stationary sled. The boy slides on the sled over a horizontal, frictionless surface at a speed of:a. 2 m/sec.b. 4 m/sec.c. 5 m/sec.d. 10 m/sec.


41. What braking force is needed to stop a 1,000-kilogram car moving at 10 m/sec in a time of 1 seconds?a. 1 newtonb. 10 newtonsc. 100 newtonsd. 10,000 newtons

ANS: DFt = mv2 −mv1

F =m v2 − v1ÊËÁÁ

ˆ¯

t=

1,000 kg 0 − 10 m/sec( )

1sec

F = −10,000 newtons


42. A 2-kilogram piece of clay moving at 4 m/sec strikes and sticks to a second 4-kilogram piece of clay moving at 1 m/sec in the opposite direction. Calculate the speed of the combined piece of clay.a. 1 m/secb. 2 m/secc. 4 m/secd. 6 m/sec

ANS: Bmomentum before collision = momentum after collision

m1v1 +m2v2 = m1 +m2ÊËÁÁ

ˆ¯v3

2 kg × 4 m/secÊËÁÁ

ˆ¯ + 4kg × 1 m/secÊ

ËÁÁˆ¯ = 2 kg+ 4 kgÊ

ËÁÁˆ¯v3


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Chapter 3: The Conservation Laws—Multi-format Bank

MODIFIED TRUE/FALSE

1. Hunters experience a “kick” when they fire a 12 gauge shotgun. This is due to the backward acceleration caused by the reaction force called recoil. _________________________


2. As a skateboarder increases her speed (or velocity) from 2 m/s to 4 m/s, she also increases her inertia. _________________________

ANS: F, momentum DIF: basic REF: section 3.1

3. “For every action there is an equal and opposite reaction” is a statement of Newton’s first law of motion. _________________________

ANS: F3rd law of motionthird law of motionthird law3rd law


4. Units for measuring impulse, newton-seconds, are equivalent to kilogram-meters per second, units for measuring momentum. _________________________


5. As the speed of a ball rolling on the floor decreases, its potential energy decreases. _________________________

ANS: Fremains the samestays the samedoes not changedoesn’t change


COMPLETION

1. As Maria steps from a small rowboat towards a pier, the boat moves away from the pier. Maria falls into the water. She is a “victim” of the law of conservation of ____________________.

ANS: momentum DIF: basic REF: section 3.1

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2. Alicia is asked to calculate the change in momentum that occurs as she stops her bicycle. This is equivalent to the ____________________ applied to the bicycle.

ANS: impulse DIF: basic REF: section 3.2

3. The expression F × t• represents _________________________.

ANS: impulsechange in momentum


4. The expression mgh represents _________________________ energy.

ANS: potentialgravitational potential


5. The kinetic energy of an object depends upon two things: ____________________ and ____________________.

ANS: mass, speedmass, velocityvelocity, massspeed, mass


6. “Energy can never be created or destroyed, just transformed from one form to another” is a statement of the law of ______________________________ (three words).

ANS: conservation of energy DIF: basic REF: section 3.3

7. The expression 12

mv 2 represents ____________________ energy.

ANS: kinetic DIF: basic REF: section 3.3

SHORT ANSWER

1. A speeding truck makes contact with a bug on its windshield. Compare the force that the bug exerts on the truck to the force the truck exerts on the bug.

ANS: The forces are the same; the collision involves an action-reaction pair of forces.


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2. When you push on your friend who is seated in a wagon, the wagon moves. According to Newton’s 1st law of motion, the force you apply to your friend is equal but opposite to the force your friend applies to you. Explain why the two equal and opposite forces do not cancel one another with no resulting motion. Tell what force does cause the motion.

ANS: The forces are applied to different objects. The force that produces the motion is the force your feet apply to the ground that is greater than the force that the ground applies to the wheels of the wagon.


3. As a tennis player, golfer, baseball player or soccer player you might be told by your coach to “follow through” when striking the ball. Explain why.

ANS: By “following through” you would maintain contact with the ball for a longer time, imparting a greater impulse, more momentum and, therefore, greater speed to the ball.


4. A ball is thrown from position (1) to a height of 5 meters above at position (2), giving the ball potential energy. The ball then falls to position (3). Assuming there is no loss of energy due to friction:

A. Name the height at which the kinetic energy of the ball would be exactly the same its potential energy?B. Compare the potential energy at (3) to the kinetic energy at (2).C. Compare the kinetic energy at (1) to the potential energy at (2).

ANS: A. At a height of 2.5 meters above position (1) the kinetic energy will equal the potential energy.B. They both will be zero at those two positions.C. They both will be the same and at their maximums.


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PROBLEM

1. Calculate the momentum of a 30-kilogram cart moving at a speed of 2.0 meters per second.

ANS: momentum = m× v = 30 kg× 2.0 m/sec

momentum = 60 kg ⋅m/sec


2. While sitting motionless on a 10-kilogram, friction-free wagon, 75-kilogram “Bozo, the human target” catches an 8-kilogram cannonball moving at 15 meters per second. After catching the cannonball, at what speed do Bozo, the wagon and cannonball move?

ANS: speed = 1.3 m/sec

Since momentum must be conserved, the momentum of the system before Bozo catches the ball must equal the momentum of the system after Bozo catches the ball. After Bozo catches the ball, the ball, Bozo and the wagon must move off at the same speed.

mb = mass of Bozomw = mass of wagonmc = mass of cannonballvb = initial speed of Bozo and wagonvc = speed of cannonballvbc = speed of all

momentum before = momentum after(mb +mw)(vb ) + (mc)(vc) = (mb +mc +mw)(vbc)(75kg + 10kg)(0m/sec) + (8kg)(15m/sec) = (75kg + 10kg + 8kg)(vbc)0 + 120kg m/sec = 93kg(vbc)vbc = 1.3m/sec


3. Calculate the size of the impulse that must be applied to stop a 200-kilogram wagon rolling on a flat path at a speed of 4.5 meters per second.

ANS: The momentum of the wagon must be reduced to zero to stop it.impulse = change in momentum = Ft = m(v2 - v1) = (200 kg)(4.5 m/sec - 0) = 900 kg·m/sec,or 900 newton-seconds


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4. Calculate the speed of a 0.25-kilogram water balloon propelled by a water balloon launcher applying an average force of 20 newtons for 0.75 seconds.

ANS: impulse = f × t = mv2 −mv1

20 N × 0.75 sec = 0.25 kg × v2ÊËÁÁ

ˆ¯ − 0.25 kg × 0Ê

ËÁÁˆ¯

v2 = 60 m/sec


5. Calculate the maximum height a 0.75-kg ball will rise if it is kicked straight up with an initial speed of 17 meters per second.

ANS: maximum height = 14.7 meterspotential energy = kinetic energypotential energy = mass × g × height

kinetic energy =12

mass × velocity2

mgh =1

2mv2

h =v2

2g=

17 m/sec( ) 2

2 × 9.8 m/sec2 = 14.7 meters


ESSAY

1. Two forces act on you when you are standing motionless on the floor, the force due to gravity and the force of the floor. These two forces are equal and opposite. Are they the action- reaction forces that are referred to in Newton’s third law? Explain your answer.

ANS: No they are not. Newton’s third law describes the result of a single action, the action between the person and Earth and Earth and the person. The two forces referred to in the question are part of two different actions, the action between the person and the floor and the action between the person and Earth.


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2. Explain why airbags in automobiles help to prevent injury.

ANS: In automobile accidents, passengers as well as drivers continue to travel in a straight line after the car has slowed drastically or even stopped quickly due to a collision. They often make contact with surfaces in the car that are very hard. A hard surface applies a large force over a short time to reduce velocity and momentum to zero. The airbag allows a smaller force to be applied over a longer time, resulting in the same impulse and change in momentum but with less serious injuries.


3. If you exert the same force on Earth that Earth exerts on you, why doesn’t Earth move up to meet you when you jump off its surface?

ANS: Although the impulse applied by each is the same, due to the much greater mass of Earth, the change in the velocity of Earth is much smaller than your change in velocity. Consequently, Earth is accelerated towards you imperceptively by this action.


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4. A 20-gram ball of clay strikes a wooden block (pictured in the diagram) at a speed of 10 cm/sec and sticks to the block. The block wiggles but does not tip over. A 20-gram “bouncy ball” traveling at 10 cm/sec strikes the same block and bounces off in the direction from which it came. This time, the block tips over. Explain why.

ANS: As the ball and block collide, momentum of the ball-block system must be conserved. As the clay ball strikes the block and stops, it imparts its momentum to the block. While momentum is conserved, its mass times its change of velocity (impulse) is not sufficient to topple the block. The bouncy ball behaves in a similar manner EXCEPT that in striking the block and bouncing back, it experiences a greater change in velocity because it has changed direction as well. Because its change in velocity is nearly twice as great, it imparts nearly twice the momentum (impulse) to the block, enough to topple the block.


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Chapter 4: Machines, Work and Energy—Multiple Choice Bank

MULTIPLE CHOICE

1. The metric unit for work is the:a. newton.b. joule.c. watt.d. meter.


2. If forces A, B and C are equal, the work done by the forces as they are exerted on the box is:

a. greatest for force A.b. greatest for force B.c. greatest for force C.d. the same for all forces.


3. A unit used to measure power is the:a. joule.b. newtons per second.c. newton-meter.d. watt.


4. An automobile jack exerts a force of 4,500 newtons to raise a car 0.25 meters. The amount of work done by the jack is about ____ joules.a. 0.00056b. 1,100c. 4,500d. 18,000


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5. A 60-newton block at rest at the bottom of a frictionless incline plane is pushed up the incline:

The amount of work done against gravity is ____ joules.a. 0b. 20c. 60d. 180


6. The action that would require no work to be done is:a. holding a 100-pound object over your head.b. pushing a 25-kilogram box of books across the floor.c. pedaling a 100-newton bicycle up a small hill.d. lifting a balloon filled with air from the floor to a desktop.


7. A 2.2-kilogram crate is pulled by a 30-newton force over a distance of 5 meters. The work done by pulling the crate is ____ joules.a. 11b. 66c. 150d. 330


8. When a force applied to an object causes the object to move in the direction of the force, the object acquires:a. energy.b. mechanical advantage.c. efficiency.d. friction.


9. Running up a flight of stairs, Maria generates 450 watts of power. If it takes her 6 seconds to go up the stairs, the amount of work she does in running up the stairs is ____ joules.a. 0.013b. 75c. 450d. 2,700


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10. Jasmine, who weighs 400 newtons, moves up a 5.0-meter climbing wall in 15 seconds. The amount of power generated by Jasmine as she climbs the wall is about ____ watts.a. 130b. 2,000c. 6,000d. 30,000


11. 60 joules of work are required to lift the 10-newton object 5.0 meters as shown in the diagram:

The amount of work done in overcoming friction as the weight is lifted is ____ joules.a. 10b. 50c. 60d. 300


12. The diagram shows a 20-newton force being used to pull a 5-kilogram object up a hill at a constant speed:

The amount of work done against gravity in moving the object from point A to point B is about ____ joules.a. 100b. 200c. 500d. 600


13. Jordan lifts a 100-kilogram barbell from the floor to a height of 2.0 meters in 1.5 seconds. The amount of power he generates is about ____ watts.a. 130b. 200c. 1,310d. 1,960


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14. An electrical water heater raises the temperature of water by adding 8,000 joules of energy to the water in 40 seconds. The minimum power that must be supplied to the heater is ____ watts.a. 0.005b. 200c. 3,200d. 320,000


15. The simple machine that operates as a ramp that curves around a shaft is a:a. rope and pulley system.b. screw.c. lever.d. gear.


16. In a theoretical machine, work output:a. can be calculated by dividing output distance by output force.b. is always greater than the work input.c. can be calculated by multiplying output force by output distance.d. is always less than the work input.


17. All of the following are considered to be simple machines EXCEPT:a. scissors.b. a bicycle.c. a jackknife.d. a see-saw.


18. The force directed along the ropes of a rope and pulley system is called:a. thread.b. lead.c. mechanical advantage.d. tension.


19. The fixed point around which levers rotate is called the:a. input arm.b. output arm.c. fulcrum.d. lever arm.


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20. Talia pulls her younger brother in a wagon 30 meters to the top of a ramp 3 meters high. If the ramp is frictionless, the mechanical advantage of this ramp is:a. 0.10b. 10c. 27d. 33


21. The mechanical advantage of a lever is the ratio of the:a. length of the input arm to the length of the output arm.b. length of the output arm to the distance the object moves.c. input force to the output force.d. input force to the distance the object moves.


22. If the top gear in each picture makes one complete turn, which bottom gear makes the greatest number of turns?

a. Ab. Bc. Cd. D


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23. The diagram illustrates a rope and pulley system being used to raise a 15-newton weight:

The tension in the rope indicated in the diagram is ____ newtons.a. 5b. 10c. 15d. 20


24. A simple machine will sometimes multiply your:a. work.b. force.c. energy.d. All of the above


25. If the output force of a lever is greater than the input force, the:a. length of the input arm is greater than the length of the output arm.b. mechanical advantage of the lever is less than one.c. mechanical advantage of the lever is equal to one.d. length of the output arm is greater than the length of the input arm.


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26. The diagram pictures a pulley system using 7 supporting ropes:

If the boy in the picture weighs 140 pounds, the number of pounds of force the baby must exert to lift the boy is:a. 70.b. 35.c. 20.d. 7.


27. The diagram shows a gear system:

If the input gear turns 12 times, the number of turns made by the output gear is:a. 12.b. 18.c. 24.d. 48.


28. A screw with a lead of 0.80 millimeters and a circumference of 24 millimeters is turned into a board using a screwdriver with a mechanical advantage of 4. The total theoretical mechanical advantage is:a. 1.3b. 3.0c. 4.8d. 120


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29. Josephine slides a 150-newton box 12 meters up an incline plane. If the incline plane lifts the box 4 meters as she pushes with a 60-newton force, the work input done by Josephine is ____ joules.a. 48b. 600c. 720d. 9,000


30. The measure of how effective a machine is in using energy to do work is called:a. work output.b. transformation.c. mechanical advantage.d. efficiency.


31. Friction is a “catch-all” term for many processes that oppose:a. heat.b. wear.c. motion.d. None of the above


32. As fuel burns in a jet engine, it releases 40,000 joules of energy. The energy can be used to do 16,000 joules of work. The efficiency of the engine is ____ percent.a. 20b. 40c. 60d. 250


33. The work output is 500 joules for a machine that is 25 percent efficient. The work output is ____ joules.a. 125b. 1,000c. 2,000d. 12,500


34. An incandescent light bulb uses 60 joules of electrical energy every second. Due to heat loss, the energy available for light is reduced to only 6 joules per second. If this bulb is used to keep eggs warm in an incubator, about how efficient is the light bulb at producing heat?a. 10 percent.b. 20 percent.c. 60 percent.d. 90 percent.


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35. Luis lifts a 500-newton load in a wheelbarrow 0.15 meters by raising the handles of the wheelbarrow 0.40 meters with a 200-newton force. The amount of work used to overcome friction is ____ joules.a. 5b. 75c. 80d. 200


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Chapter 4: Machines, Work and Energy—Multi-format Bank

MODIFIED TRUE/FALSE

1. The rate of doing work is called energy. _________________________

ANS: F, power DIF: basic REF: section 4.1

2. The unit for power equal to one joule of work divided by one second of time is called a watt. _________________________


3. The work a machine does for you is called the input work. _________________________

ANS: F, output DIF: basic REF: section 4.2

4. The point around which a lever rotates is called the arm of the lever. _________________________

ANS: F, fulcrum DIF: basic REF: section 4.2

5. The measure of how effective a machine is in using its energy to do work is known as the friction of the machine. _________________________

ANS: F, efficiency DIF: basic REF: section 4.3

COMPLETION

1. The transfer of energy that results from applying a force over a distance is called ____________________.

ANS: work DIF: basic REF: section 4.1

2. If Sam pushes a block one meter with a force of one newton, he has done one ____________________ of work on the block.

ANS: joule DIF: basic REF: section 4.1

3. For an object to do work, it must possess ____________________.

ANS: energy DIF: basic REF: section 4.1

4. If Gabriela pushes on a box with a 20-newton force, no work is done if the box does not ____________________.

ANS: move DIF: basic REF: section 4.1

5. The work Brandon does in lifting a rock is calculated by multiplying the weight of the rock by the change in the ____________________ of the rock.

ANS: height DIF: basic REF: section 4.1

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6. A device with moving parts that work together to accomplish a task is called a ____________________.

ANS: machine DIF: basic REF: section 4.2

7. The ratio of the output force to the input force is called _________________________ (two words).

ANS: mechanical advantage DIF: basic REF: section 4.2

8. The pulling force that always acts along the direction of the rope in a pulley system is called ____________________.

ANS: tension DIF: basic REF: section 4.2

SHORT ANSWER

1. On Monday, Bik runs upstairs carrying a heavy book. The next day, she walks upstairs carrying the same book. Compare Bik’s work and power on Monday and Tuesday.

ANS: The work done by Bik on both days is the same, but she generated more power on Monday as she ran up the stairs.


2. List four types of simple machines.

ANS: Answers may vary. Correct answers include:wheel and axle, rope and pulleys, ramp, gears, lever, screws


3. Name the three basic parts of a lever.

ANS: input arm, output arm, and fulcrum


4. State the relationship between the mechanical advantage of a pulley system and the number of strands supporting the pulley.

ANS: The mechanical advantage of a pulley system is equal to the number of supporting strands.


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5. Compare the output work to the input work for a machine.

ANS: The work output is never greater than the work input. In fact, the work output would equal the work input in a perfect machine.


6. Name the quantity represented by each of the ratios below:

a. ____________________ =output forceinput force

b. ____________________ =workoutputwork input

c. ____________________ =worktime

ANS: a. mechanical advantageb. efficiencyc. power

DIF: intermediate REF: section 4.1, section 4.2, section 4.3

PROBLEM

1. If one horsepower is equal to 746 watts, how much horsepower does a highly trained athlete generate by doing 350 joules of work per second for an hour?

ANS: 0.469 horsepower

power =worktime

=350 joules

second= 350 watts

1 horsepower = 746 watts

power = 350 watts ×1 horsepower

746 watts= 0.469 horsepower


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2. Calculate the power required to move a 2,000-kilogram automobile to the top of a 100-meter hill in 15.0 seconds. Express the power both in units of watts and horsepower.

ANS: power = 130,667 watts = 175 horsepower

power =worktime

=force×distance

time=

mass×g ×heighttime

power =2,000 kg×9.8 m/sec2 ×100 m

15 sec= 130,667 watts

power =130,667 watts746 watts/hp

= 175 horsepower


3. Carlos accelerates his 3-kilogram skateboard to a speed of 3.96 m/sec in 3 seconds in a distance of 4 meters. How much work does he do?

ANS: 15.8 jouleswork = force × distance = mass × acceleration × distance

work = mass ×∆ velocity∆ time

work = 3 kg ×3.96 m/sec

3 sec× 4 m = 15.84 joules


4. Calculate the theoretical mechanical advantage of a ramp that is 2 meters high and 10 meters long.

ANS:

MA =ramp lengthramp height

=10 meters2 meters

= 5


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5. How much force would be required to lift a 350-newton weight by using a pulley system with a mechanical advantage of 5?

ANS: 70 newtons

MA =output forceinput force

output force =input force

MA=

350 N5

= 70 newtons


6. A 70-kilogram bicycle racer climbs a 500-meter hill by doing 400,000 joules of work. Calculate the efficiency of his bicycle.

ANS: 86 percent efficient

work output = mass × g × height = 70 kg × 9.8 m/sec2 × 500 m

work output = 343,000 joules

efficiency =work outputwork input

× 100

efficiency =343,000 J400,000 J

× 100 = 85.75 percent


ESSAY

1. Explain the following statement: “Applying a force to an object does not necessarily give the object energy.”

ANS: For mechanical energy to be transferred to an object, work must be done on the object. Work is the product of force AND the distance the object moves in the direction of the applied force. It is possible to apply a force on an object with no resulting movement. Unless the object moves when the force is applied, no mechanical energy is absorbed by the object.


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2. Isaiah and Ben have a race to carry identical objects from a point at the bottom of a hill to the same point at the top. Isaiah runs straight up a very steep part of the hill and finishes first. Ben chooses a more gradual ascent and, walking, arrives after Isaiah. Who has done more work? Explain your answer.

ANS: Isaiah and Ben do the same amount of work. The work is done against gravity:work = mass × g × height.Since the objects are identical, they have the same mass and are lifted the same distance against gravity. The value for g, the acceleration due to gravity, is a constant for the objects. The work done is independent of the path. (Because Isaiah finished the work in less time, he did produce more power.)


3. Describe each type (class) of lever, and give an example of each class.

ANS: The first class lever is arranged with the fulcrum between the input arm and the output arm. Examples include pliers, scissors, and a see-saw.

The second class lever is arranged with the output arm between the fulcrum and input arm. Examples include a wheelbarrow, a door on hinges, and the cover on a book

The third class lever is arranged with the input arm between the fulcrum and the output arm. Examples include a fishing pole, moving bones of the body, and a tennis racket.


4. Explain why the efficiency of machines is always less than 100 percent. In the discussion, use the words efficiency, work input, work output, heat, and friction.

ANS: In a machine, surfaces rubbing together causes friction. The friction produces heat, which increases the temperature of the surrounding air and the machine. The heat dissipated to the air and the machine reduces the work output to a level less than the work input. Since the efficiency of a machine is the ratio of the work output to the work input, the efficiency of all machines is less than 100%.


5-59

Chapter 5: Forces in Equilibrium—Multiple Choice Bank

MULTIPLE CHOICE

1. A word meaning “size”often used to describe scalar quantities is:a. magma.b. magenta.c. vector.d. magnitude.


2. A measured quantity that is described by stating a size and a direction is called a:a. scalar.b. magnitude.c. vector.d. victim.


3. If a force vector acting in a northeast direction is resolved into its components, any vector acting in the north-south direction would be called a(n):a. hypotenuse.b. x-component.c. y-component.d. resultant.


4. Vector quantities include all of the following EXCEPT:a. velocity.b. force.c. speed.d. acceleration.


5. A scalar is a quantity that can be completely described using:a. direction only.b. magnitude only.c. both magnitude and direction.d. either magnitude or direction.


6. Jade pulls on a wagon with 3 newtons of force toward north. Lara pulls on the wagon with 4 newtons of force toward east. The magnitude of the wagon’s resultant force is ____ newton(s).a. 1b. 5c. 7d. 25


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7. Forces in a diagram are represented by the following scale: 1 centimeter equals 5 newtons. To represent a force of 20 newtons, the length of an arrow drawn to represent the force should be ____ centimeter(s).a. 1b. 4c. 5d. 20


8. Lily pushes a box with 50 newtons toward east. Mia pushes on the same box with 50 newtons toward south. The direction of the box’s resultant force is most clearly stated as:a. 45º.b. 135º.c. 225º.d. 315º.


9. The diagram below represents a force acting at point P:

The pair of forces that could represent x and y components of this force are:a. 1b. 2c. 3d. 4


10. Maya kicks a soccer ball 2 newtons toward north. At the exact same time, Casey kicks the same ball toward west. The resultant force of the soccer ball is about 36 newtons. The force that Casey kicks the soccer ball toward west is ____ newtons.a. 16b. 20c. 30d. 56


11. The relationship between a spring’s change in length and the force it exerts is called:a. Newton’s law.b. Hooke’s law.c. Archimedes’ principle.d. Galileo’s theory.


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12. When a spring is compressed:a. the potential energy stored in the spring increases.b. the potential energy stored in the spring decreases.c. the spring constant of the spring is decreased.d. the spring constant of the spring is increased.


13. When the net force acting on an object is zero, this ALWAYS causes a condition of motion referred to as:a. rest.b. positive acceleration.c. negative acceleration.d. equilibrium.


14. When you are seated in a chair, the force exerted on you by the chair is called the:a. normal force.b. gravitational force.c. weight.d. mass.


15. A dictionary whose mass is 1.0 kilograms lying on a stationary table exerts a force of 9.8 newtons on the table. The force exerted on the dictionary by the table is ____ newtons.a. 1.0b. 8.8c. 9.8d. 10.8


16. A car drives from east to west over a bridge supported by the ground at either end as illustrated in the diagram:

The force exerted by the ground on the bridge at the west end is ____ tons.a. 58b. 39c. 20d. 19


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17. Eric is pedaling his bicycle due west on the Mohawk River bicycle path at a constant speed of 17 miles per hour. As he is pedaling, a 3 mile per hour wind is blowing from the east. The statement that best describes the forces acting on Eric’s bicycle is:a. the net force acting on the bike is zero.b. a greater net force is acting toward the east.c. a greater net force is acting toward the west.d. Not enough information is given to answer the question.


18. A force of 2 newtons is required to stretch a spring 4 centimeters. The amount of force required to stretch the same spring 8 centimeters is ____ newton(s).a. 1b. 2c. 4d. 8


19. If the stretching force on a spring is doubled, the length of the spring will be:a. unchanged.b. doubled.c. quadrupled.d. halved.


20. A spring with a large spring constant:a. always stretches a large amount.b. never stretches a large amount.c. stretches a large amount with a small force.d. stretches a small distance with a large force.


21. The force that resists the motion of objects or surfaces in contact with one another is called ____ force.a. inertialb. frictionalc. normald. net


22. The force of friction between two surfaces can be reduced by all of the following EXCEPT:a. separating surfaces with a lubricant.b. changing rolling friction to sliding friction.c. separating surfaces with a layer of air.d. sanding rough surfaces smoother.


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23. Two moving surfaces are in contact with one another. The force of friction between the surfaces can be changed by all of the following methods EXCEPT:a. placing lubrication between the surfaces.b. changing the types of surfaces.c. changing the force used to move the surfaces.d. altering the force pushing the two surfaces together.


24. To overcome static friction to start an object sliding on a level surface, a 100-newton force is used. The magnitude of the force needed to keep the object the sliding is:a. more than 100 newtons.b. equal to 100 newtons.c. less than 100 newtons.d. unknown using the given information.


25. Of the following, the statement about friction which is NOT true is:a. friction is always present.b. friction can be useful.c. friction can be harmful.d. friction can be eliminated.


26. As Joshua accelerates in his pickup truck at 2.0m/sec2, a 200-kilogram box in the back does not slide. The force of friction that must act on the box to keep it from slipping in the back of the truck is ____ newtons.a. 100b. 200c. 400d. 1,960


27. The diagram below represents a box sliding down an incline:

The force of friction acting on the box is directed toward:

a. 1b. 2c. 3d. 4


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28. Pulling on a rope with a force of 100 newtons at an angle θ of 30 degrees, Cheung pulls a box across a surface at a constant speed:

The magnitude of the frictional force resisting the motion is ____ newtons.a. 100b. 87c. 50d. 0


29. The line about which an object turns is called the:a. torque.b. axis of rotation.c. radius.d. lever arm.


30. As the force applied to a rotating object is moved farther from the axis of rotation, the torque created by the force:a. increases.b. decreases.c. is always clockwise.d. is always perpendicular to the lever arm.


31. Aaron applies a 70.0-newton force to the handle of a wrench at a distance of 0.350 meters from the nut on the axle of his bicycle wheel. The amount of torque applied to the nut is ____ newton-meters.a. 0.005b. 24.5c. 70.35d. 200


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32. The diagram represents a lever to which forces are applied:

To create rotational equilibrium, the force exerted at the left end of the lever must be ____ newtons.a. 36b. 27c. 12d. 4


33. Juan and his younger sister Ana are able to balance when seated on a see-saw. Juan weighs 800 newtons and sits 2.0 meters from the balance point. Ana weighs 400 newtons.

To create rotational equilibrium, the distance she must sit from the balance point is ____ meter(s).a. 1.0b. 2.0c. 4.0d. 8.0


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Chapter 5: Forces in Equilibrium—Multi-format Bank

MODIFIED TRUE/FALSE

1. A measured quantity that includes both a direction and magnitude is called a scalar quantity. _________________________

ANS: F, vector DIF: basic REF: section 5.1

2. The relationship between a spring’s change in length and the force it exerts is called Newton’s law. _________________________

ANS: F, Hooke’s DIF: basic REF: section 5.2

3. The force exerted by a table perpendicular to its surface upon a book resting on the table is called the resultant force. _________________________

ANS: F, normal DIF: intermediate REF: section 5.2

4. The force required to overcome static friction is less than the force to overcome sliding friction. _________________________

ANS: Fmoregreater


COMPLETION

1. A fluid such as oil used to reduce friction is called a ____________________.

ANS: lubricant DIF: basic REF: section 5.3

2. The rotational equivalent of force that causes objects to rotate about a point is called ____________________.

ANS: torque DIF: basic REF: section 5.4

3. A see-saw that is balanced has a net torque of zero applied to it. It is said to be in _________________________ (two words).

ANS: rotational equilibrium DIF: basic REF: section 5.4

4. The size of a scalar or vector quantity may be called its ____________________.

ANS: magnitude DIF: basic REF: section 5.1

5. The sum of two or more vectors is called the ____________________.

ANS: resultant DIF: basic REF: section 5.2

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6. When the net force that acts on a body is zero, the forces are balanced. This represents a condition called ____________________.

ANS: equilibrium DIF: basic REF: section 5.2

7. A diagram that uses vectors to show all of the forces acting on an object is known as a ____________________ diagram.

ANS: free-bodyfree body

DIF: basic REF: section 5.1, section 5.2

SHORT ANSWER

1. List three ways to reduce friction.

ANS: Answers may vary. Correct answers include:1. Lubrication2. Smoothing rough contacting surfaces3. Changing sliding friction to rolling friction4. Changing sliding friction to fluid friction by putting air between the contacting surfaces


2. Identify each of the following as a scalar or vector quantity:a. speedb. massc. velocityd. lengthe. temperaturef. timeg. weight

ANS: a. scalarb. scalarc. vectord. scalare. scalarf. scalarg. vector


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PROBLEM

1. Using a scale of 1 centimeter = 1 newton, represent the following displacement vectors:(a) 5 newtons west(b) 3 newtons, 270º(c) 4 newtons, 0º

ANS:


2. Alexis pulls with 3 newtons on a toy doll toward east. Brianna pulls on the same toy toward south with 2 newtons. Calculate the magnitude of the resultant force on the toy.

ANS: 3.6 newtonsUsing the Pythagorean theorem:

FTÊËÁÁ

ˆ¯

2= 3 N( ) 2 + 2 N( ) 2

FT = 3 N( ) 2 + 2 N( ) 2 = 3.6 N


3. A scale of 1 centimeter = 1 newton was used to draw the vector represented. Using a centimeter ruler, draw and identify the magnitude of the horizontal and vertical components of the 4.5-newton force illustrated in the vector drawing below:

ANS:


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4. A can of soda sits motionless on a table. Make a free-body diagram of the forces acting upon the can.

ANS:


5. When a 20-newton weight is hung on a spring, it stretches 16 centimeters. How far does the spring stretch if a 5.0-newton weight is hung from the spring?

ANS: 4 centimeters

20 N16 cm

= 5.0 N

? =

16 cm× 5.0 N20 N

= 4 cm


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6. The diagram below represents a lever with three forces applied to it at different positions. A four-newton, clockwise force is applied one meter from the right end of the lever. A ten-newton, clockwise force is applied 5 meters to the left of the four newton force.

For the lever to be in equilibrium, what is the size of the counterclockwise force applied four meters from the right end of the lever?

ANS: 16 newtons

clockwise torque equals counterclockwise torque(10N × 6m) + (4N × 1m) =?× 4m

64 N-m4 m

= 16N


ESSAY

1. Friction can be useful, but it is often desirable to reduce the amount between surfaces. List 3 examples of useful friction and 3 examples of friction that should be reduced.

ANS: Answers may vary. Correct answers include:Useful friction:(a) The friction between the tires of a car and the road when rounding a curve(b) The friction between your hands and the top of a jar when you are twisting its top off(c) The friction between the disk brake pads and the disc brakes used to stop a moving car(d) The friction between sandpaper and wood when trying to smooth the wood

Annoying friction:(a) The friction between the axle of a wheel and the bearings(b) The friction between a box and the floor when sliding the box on the floor(c) The friction between both the air and road surface and an automobile as it moves on a level turnpike


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2. Explain why it is easier to open a door when pushing on the edge of the door close to the doorknob than pushing on the edge closer to the hinges.

ANS: The action that causes an object to turn is called torque. When more torque is applied to an object it has a greater tendency to rotate. The farther a force is applied from the axis of rotation, the greater the torque. Since the axis of rotation is in the middle of the hinges of the door, the application of force further from the hinges will create a greater tendency to rotate.


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Chapter 6: Systems in Motion—Multiple Choice Bank

MULTIPLE CHOICE

1. The parabolic path followed by a projectile is referred to as the:a. range.b. trajectory.c. circumference.d. ellipse.


2. A golf ball will have the greatest range when it is hit an angle of:a. 30º.b. 45º.c. 60º.d. 90º.


3. The distance a projectile travels is dependent upon:a. air resistance.b. launch angle.c. launch speed.d. All of the above


4. The distance a projectile travels horizontally in the air may be called its:a. trajectory.b. range.c. parabola.d. height.


5. If a ball thrown horizontally with a speed of 15 meters per second travels for 5 seconds before hitting the ground, its range after 4 seconds would be about ____ meters.a. 15b. 39c. 60d. 153


6. Of the following, the one that would NOT be considered a projectile is a:a. crow flying between trees.b. football thrown by a high school quarterback.c. tennis ball hit by a star tennis player.d. fox jumping over a wall.


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7. Jennifer and Tamar throw a snowballs at the same time horizontally from a height of 1.5 meters. Jennifer throws hers at a speed of 6.0 meters per second. If Tamar throws hers at 12 meters per second, her snowball will:a. travel the same distance as Jennifer’s before hitting the ground.b. hit the ground later than Jennifer’s.c. travel the half the distance as Jennifer’s before hitting the ground.d. hit the ground at the same time as Jennifer’s.


8. The golf ball that will travel farthest is one hit at an angle of:a. 20º.b. 30º.c. 40º.d. 60º.


9. If a ball thrown horizontally with a speed of 15 meters per second travels for 5 seconds before hitting the ground, its horizontal speed after 4 seconds is ____ m/sec.a. 15b. 39c. 60d. 75


10. A stunt car driver traveling at 30 meters per second drives his car off a 20 meter high cliff as illustrated in the diagram:

How far from the base of the cliff does the car hit?a. 41 metersb. 61 metersc. 82 metersd. 122 meters


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11. A soccer ball is kicked into the air with an initial vertical velocity of +49 meters per second and a horizontal velocity of +19.6 meters per second. The diagram representing the vertical and horizontal velocity of the ball after 2 seconds of flight is:

a. Ab. Bc. Cd. D


12. A water balloon leaves a launcher at a certain speed and travels 125 yards when launched at an angle of 23º to the ground. If launched at the same speed, it would travel the same distance when launched at an angle of:a. 22º.b. 46º.c. 67º.d. 77º.


13. A projectile launched at a speed of 35 meters per second will have the greatest horizontal speed when launched at an angle of:a. 20º.b. 30º.c. 45º.d. 60º.


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14. Angular speed can measure:a. the rate at which an object moves in a straight line.b. the rate at which an object revolves around an external axis.c. the rate at which an object rotates around an internal axisd. both the rate of rotating and revolving.


15. An example of rotation is:a. Earth moving in its orbit around the sun.b. a basketball spinning on the end of a finger.c. a race car traveling at 200 miles per hour around a circular track.d. a student riding at the outside position on a merry-go-round.


16. Mao watches a merry-go-round as it turns 27 times in 3 minutes. The angular speed of the merry-go-round is ____ rpm.a. 81b. 27.c. 9d. 0.11


17. Three students are seated on a merry-go-round. Randy is seated closest to the center, Toby is seated near the outer edge, and Rasheed is seated between them. As the merry-go round turns:a. Randy has the greatest linear speed but the lowest angular speed.b. Toby has the highest linear speed and the same angular speed as the others.c. Rasheed has the same linear speed as the others but the highest angular speed.d. All three students have the same linear and angular speed.


18. Anika twirls a ball on a string which is 3.0 meters long. If the ball makes 2 revolutions per second, the linear speed of the ball is about ____ m/sec.a. 6b. 10c. 19d. 38


19. Spiderman swings on the end of a web that is 20 meters long in an arc of 45 degrees to get from one building to another. The trip takes him 5.0 seconds. Spiderman travels from building to building at a linear speed of about ____ m/sec.a. 2.0b. 6.3c. 10d. 31


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20. A record rotating a 33 RPM’s has an angular speed of:a. 33º/min.b. 55º/sec.c. 198º/sec.d. 55º/min.


21. Erica pedals her bicycle from home to a local store 2.5 miles (13,200 feet) away. The wheels on Erica’s bicycle have a diameter of 27 inches. The number of revolutions made by the wheels of her bicycle on this ride is about:a. 1,100.b. 1,900.c. 13,000.d. 22,000.


22. The speedometer on a bicycle registers speed by converting angular speed of the bicycle’s wheel to linear speed. What is the approximate speed that would be indicated by the speedometer of a bicycle wheel with a diameter of 0.70 meters rotating at a rate of 3.0 rotations per second?a. 2.2 m/secb. 4.3 m/secc. 6.6 m/sec.d. 21 m/sec.


23. Any force that causes an object to move in a circle is called ____ force.a. gravitationalb. centripetalc. lineard. frictional


24. The source of the centripetal force that allows a race car to go around a corner is:a. gravity.b. friction.c. inertia.d. momentum.


25. The weight of an automobile depends upon all of the following factors EXCEPT the:a. speed of the automobile on the road.b. mass of the earth.c. mass of the automobile.d. distance of the automobile from the Earth’s center.


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26. You cannot feel a gravitational force acting between you and a friend because:a. gravity is a force applied only by Earth.b. living things do not exert any gravitational force.c. the mass of a person is not large enough to exert gravitational force that can be felt.d. the distance between attracting objects must be very large for gravity to act.


27. The path followed by one object as it revolves around another is called its:a. trajectory.b. orbit.c. satellite.d. center of mass.


28. Factors that affect the amount of centripetal force on an object moving in a circle include all of the following EXCEPT:a. speed of the object.b. radius of revolution.c. mass of the object.d. direction of motion (clockwise or counterclockwise).


29. All of the following represent objects that are being accelerated EXCEPT a:a. car moving around a corner at a constant speed of 30 miles per hour.b. competitor in a track meet increasing speed at the finish line to pass another runner.c. bird flying in a straight line from one tree to another at high speed.d. jet airliner banking into a turn as it slows to prepare for a landing.


30. According to the diagram, the direction of the centripetal force on the airplane is directed toward:

a. Ab. Bc. Cd. D


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31. If you climb a hill, you are farther from the center of Earth. Due to your new location, your weight will:a. decrease by a tiny amount.b. decrease by a large amount.c. increase by a tiny amount.d. increase by a large amount.


32. The factor that will INCREASE your weight the MOST is:a. doubling your mass.b. halving your mass.c. doubling your distance from the Earth’s center.d. halving your distance from the Earth’s center.


33. If the radius of the curve around which a car is driven is increased, the following can be said about the centripetal force required to cause the car to go around the corner at constant speed:a. The centripetal force increases.b. The centripetal force decreases.c. The centripetal force remains the same.d. There is insufficient information to make a determination about the centripetal force.


34. A ball is being twirled on the end of a string as pictured in the diagram:

If the string is released when the ball reaches point P, the inertia of the ball will cause it to move in the direction of:a. Ab. Bc. Cd. D


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35. The centripetal force on a 20-kilogram object revolving on the end of a 10-meter long cord is 20 newtons. If the linear speed of the object is doubled, the centripetal force required to keep it moving in a circle of the same radius is ____ newtons.a. 10b. 40c. 80d. 200


36. Examples of centripetal force includes all of the following EXCEPT:a. gravity of the sun acting to keep Earth in orbit.b. the door of a car pushing on a passenger as the car rounds a corner.c. the friction between a dragster and the track as the car accelerates down the drag strip.d. the force of the air pushing on the wings of a plane as it makes a turn.


37. The force required to keep an object moving in a circle of the same radius while its mass is doubled and its speed is reduced to half would be:a. the same.b. doubled.c. halved.d. quadrupled.


38. If the distance between two objects is doubled while the masses of both objects are doubled, the gravitational force between them is:a. halved.b. the same.c. doubled.d. quadrupled.


39. The mass of the planet Jupiter is 318 times greater than the Earth’s mass, and its radius is 11.2 times greater than that of the Earth. If it were possible to stand on the outermost region of Jupiter, your weight would be:a. 318 times greater than on Earth.b. 28.4 times greater than on Earth.c. 2.54 times greater than on earthd. 318 times less than on Earth.


40. The point around which an object naturally spins is called its:a. trajectory.b. orbit.c. satellite.d. center of mass.


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41. A sport utility vehicle will roll over if the:a. center of gravity is raised above its area of support.b. area of support includes the center of mass.c. center of mass passes outside of the area of support.d. torque caused by the object’s weight is balanced.


42. The center of mass of an object:a. is always the same as the center of gravity.b. does not exist if the object has an irregular shape.c. is sometimes outside of the object.d. is always somewhere inside the object.


43.

This toy bird balances on the tip of the finger because:a. the torque caused by the force of the bird’s weight is greater at the beak than the tail.b. the center of gravity is in line with the finger.c. the bird’s weight is outside its area of support.d. It can’t possibly balance like that. It must be glued onto the finger.


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Chapter 6: Systems in Motion—Multi-format Bank

MODIFIED TRUE/FALSE

1. The path followed by a projectile whose motion is affected only by gravity is a hyperbola. _________________________

ANS: F, parabola DIF: basic REF: section 6.1

2. The horizontal distance a projectile travels is called its trajectory. _________________________

ANS: F, range DIF: basic REF: section 6.1

3. The time a golf ball is in the air and its height are greatest when the ball is fired at an angle of 45º. _________________________

ANS: F9090 degrees90º


4. An object that moves around an external axis is said to be rotating. _________________________

ANS: F, revolving DIF: basic REF: section 6.2

5. The distance around a circular object may correctly be called its diameter. _________________________

ANS: F, circumference DIF: basic REF: section 6.2

6. The force that exists between you and Earth is correctly identified as your mass. _________________________

ANS: F, weight DIF: basic REF: section 6.3

7. The circular orbit that some satellites follow is a special case of the shape of orbit followed by most satellites. That oval-shaped orbit is called an apostrophe. _________________________

ANS: F, ellipse DIF: basic REF: section 6.3

8. As comets approach the sun in their orbits, their speed increases. _________________________

ANS: T DIF: advanced REF: section 6.3

COMPLETION

1. The path that a projectile follows after being fired is called its ____________________.

ANS: trajectory DIF: basic REF: section 6.1

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2. The vertical and horizontal components of a projectiles motion are ____________________ of one another.

ANS: independent DIF: basic REF: section 6.1

3. If a ball, fired as a projectile, travels 30 meters when it leaves the ground at a 20º angle, it will travel the same distance when fired at an angle of ____________________ degrees.

ANS: 70 DIF: intermediate REF: section 6.1

4. The rate of revolving or rotating is described as spins per unit of time, called ____________________ speed.

ANS: angular DIF: basic REF: section 6.2

5. A vertical line around which an object may rotate or revolve is called its internal or external ____________________.

ANS: axis DIF: intermediate REF: section 6.2

6. Any force which causes an object to move in a circle is called a ____________________ force.

ANS: centripetal DIF: basic REF: section 6.3

7. The name commonly given to the centripetal force acting between the sun and Earth that keeps Earth in orbit around the sun is called the force of ____________________.

ANS: gravity DIF: basic REF: section 6.3

8. Scientists call an object that orbits another object a ____________________.

ANS: satellite DIF: basic REF: section 6.3

9. The average position of all the particles that make up the mass of an object is called its ____________________ (three words).

ANS: center of mass DIF: basic REF: section 6.4

SHORT ANSWER

1. Name three factors that can affect the range of a projectile.

ANS: The range of a projectile is determined by its initial velocity, launch angle, and air resistance.


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2. Of the following flying objects, list those that are projectiles:a. A jet plane just after take-offb. A baseball hit by a star baseball playerc. A free-throw after being released by a basketball playerd. A rock thrown from a bridge into a river belowe. A bird flying between treesf. A young woman diving from the starting block into a swimming pool

ANS: b. baseballc. free-throwd. rockf. diver


3. Projectile motion may be separated into two components, vertical and horizontal. In addition to the difference in their directions, state another difference between these motion vectors.

ANS: The vertical component is accelerated (non-constant) while the horizontal component is constant.


4. Malik and Destiny are seated on a moving merry-go-round. Malik is closer to the center than Destiny. Briefly describe the similarity or difference in their speeds in terms of angular speed and linear speed.

ANS: Since Malik is located closer to the center than Destiny, his linear speed is less than Destiny’s, but his angular speed is the same.


5. List examples of three objects that are revolving and three that are rotating.

ANS: Answer may vary. Correct answers include:Revolving1. Earth moving around the sun once each year2. A ball on a string being swung around over your head in a circle3. A race car traveling around a circular track

Rotating1. Earth turning on its axis once each day2. A CD spinning in a player.3. The propeller of an airplane spinning


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6. If the distance between two objects is doubled, what happens to the force of gravity between them?

ANS: The force of gravity will be reduced to one quarter of the original value.


7. Briefly describe how you might lose weight simply by changing your location.

ANS: You can lose weight by moving to a higher elevation.

Additional info: If you move to a location of higher elevation, you are further from the center of Earth. Since you are further from the center of Earth, the force between you and Earth will be reduced—you have lost weight. The amount lost is of little significance, however, because you are only slightly further from the center when compared to the radial distance from the center of Earth to its surface.


8. Imagine you are twirling a ball tied to the end of a string in a counterclockwise direction above your head. Draw a circle to represent the path of the ball. On that circle draw arrows to represent the following:(a) The direction of the speed of the ball; label it V.(b) The direction of the acceleration of the ball; label it A.(c) The direction of the centripetal force on the ball; label it F.

ANS: Note: Because the direction of the force and the acceleration are the same, only one arrow is used to represent both quantities in the answer.


PROBLEM

1. A bowling ball rolls off a horizontal loading platform 2.0 meters high with a speed of 3.0 m/sec. How long will it take to hit the ground?

ANS: 0.64 seconds

d = Vit + 1/2(a)t2

2.0 m = 0 + 1/2(9.8 m/sec2)t2

t2 = 0.498 sec2 = 0.639, or 0.64 sec


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2. A quarterback throws a football, giving it a vertical velocity of 9.2 meters per second and a horizontal velocity of 25.4 meters per second. Calculate the vertical and horizontal components of the football’s velocity after 1.00 second.

ANS: vertical: 0.6 m/sec downwardhorizontal: 25.4 m/sec

Vy = Vi + gt = 9.2 + (9.8 m/sec2)(1s) = 0.6 m/secVh is constant; Vh = 25.4 m/sec


3. A rocket is fired into the air with vertical velocity of 58.8 meters per second.and a horizontal velocity of 21.3 meters per second. Assuming the rocket is in free-fall, calculate the range of the rocket.

ANS: 256 meters

(1) Calculate the time the rocket is in the air.Since it returns to the ground, in the equation:d = Vit + 1/2(a)t2, d =0, Vi = the vertical velocity, t = the time in the air, and a = g(-9.8 m/sec2);0 = 58.8 m/sec(t) + 1/2(-9.8m/sec2)t2

t = 12 seconds

(2) Calculate the range.In the equation:dx = Vxt, dx = the range, t = the time in the air, and Vx = the horizontal velocity.dx = (21.3 m/sec)(12s) = 255.6, or 256 meters


4. Calculate the angular speed of a bicycle wheel that makes 240 rotations in 6 minutes.

ANS:

angular speed =rotationsminute

=240 rotations

6 minutes= 40 rpm


5. Calculate the number of degrees a wheel has rotated when it has gone twice around.

ANS: There are 360 degrees in one rotation. In two rotations, there are 2 × 360º, or 720º.


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6. A barrel with a circumference of 2.0 meters rolls 12 meters in 3.0 seconds. Calculate the angular speed of the barrel.

ANS: Since the barrel makes 6 revolutions (12 meters/2 meters) in 3.0 seconds, its angular speed is 2 revolutions per second.


7. Use the information below to calculate the weight of a 2,000-kilogram car on Earth’s surface.G, the universal gravitational constant = 6.67 × 10-11Nm2/kg2

Mass of Earth = 5.97 × 1024 kgRadius of Earth = 6.38 × 106 m

ANS:

Fg = Gm1m2

r2 =(6.67 × 10−11Nm2 / kg2 )(2,000 kg)(5.97× 1024 kg)

(6.38 × 106 m)2 =

(6.67 × 10−11 Nm2 / kg2 )(2,000 kg)(5.97 × 1024 kg)(6.38 × 106m)2 = 1.96 × 104 newtons

Note: Students could arrive at the same answer using Newton’s second law, W = mg.W = 2,000 kg × 9.81 m/sec2


8. The centripetal force needed to cause a 2,000-kilogram truck to safely round a curve at 15 meters per second is 13,000 newtons. If a 2,000-kilogram load is added to the truck but the driver cautiously slows to 7.5 meters per second in rounding the curve, how much force is required to safely negotiate the curve?

ANS: 6,500 newtonsDoubling the mass doubles the force required; reducing the speed by one-half reduces the force needed to one-quarter. The net effect is to cause an overall reduction to one-half of the original force.


9. Two objects are placed near one another. The mass of one object is doubled while the distance between the objects is tripled. What net change takes place in the force of gravity between the objects?

ANS: The force of gravity will be increased by two times because the mass of one object is doubled. The force of gravity will be reduced by 9 times the original value because the distance is increased by 3 times. The net overall effect is to reduce the force of gravity to 2/9 of its original value.


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ESSAY

1. Explain the statement, “The horizontal and vertical components of a projectile’s velocity are independent of each other.”

ANS: Two objects start from the same height above a horizontal plane. If one object is fired at high speed horizontally as the other is dropped vertically, the two objects will strike the ground at the same time. The horizontal speed has no effect on the vertical speed. Both objects will be accelerated toward the ground at the same rate, 9.8 m/sec2. In short, components that act at right angles to one another have no effect on one another.


2. Speedometers measure the speed of an automobile by measuring the angular speed of the wheels and converting it to linear speed.If Carlos customizes his car by using larger wheels than those used by the auto maker, this will affect the reading of his speedometer. Explain how and why the speedometer’s reading will be affected.

ANS: The speedometer of Carlos’s automobile will read a speed that is slower than his actual speed. The speedometer is adjusted to read the correct linear speed of the car with a certain size of wheel in place on the car. Since the wheels are larger in circumference, they will not make as many rotations at the same linear speed as a smaller wheel. His speedometer will, therefore, register a slower-than-actual speed.


3. Centripetal force must be applied to an automobile for it to follow a curved path. Explain why it is a good idea to reduce speed when going around a sharp curve. In your discussion, mention the source of the centripetal force and the effect of both speed and the radius of the curve.

ANS: The centripetal force exerted on an object changes with the square of its linear speed. If the speed is doubled, the centripetal force must be increased by four times. Reducing speed to one-half the original speed reduces the amount of centripetal force to 1/4 of the amount needed at the higher speed. Also, reducing the radius of a turn to one-half (making the turn sharper) requires twice the centripetal force. Since the centripetal force, which is supplied by the friction between the road and the tires, is nearly constant, traveling at excessive speed will require a force exceeding that supplied by friction. The car will not go around the turn.


4. Describe the relationship that exists for the force between two masses of uniform density and the distance between their centers.

ANS: The force that exists between two masses of uniform density is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.


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5. Describe how you would find the center of mass of an irregularly shaped piece of cardboard and how you could check to be sure your determination is correct.

ANS: Hang the piece of cardboard from a string. Draw a line on the cardboard in line with the string. Hang the cardboard once more by attaching the string at a different point. Draw a line from the string once more. The point where the drawn lines cross is the center of mass. To check your work, try to balance the cardboard on your fingertip by placing it under the point you have determined to be the center of mass. If you are correct, the cardboard will balance because the center of mass and the center of gravity are, in this case, the same point.


6. Explain why increasing the width between the wheels of a car makes it more stable.

ANS: Stability is determined by the positions of the center of gravity and the area of support for an object. As long as the weight (force) vector extended falls within the area of support, the object is stable and will not turn over. If the force vector moves outside the area of support, the object will topple. Increasing the area of support by increasing the width between the wheels of a car decreases the chances that the weight vector of the car will move outside its support base, the wheels, thereby reducing the risk of rollover.


7. Explain the difference between centripetal and centrifugal forces.

ANS: Centripetal force is the force that causes objects to move in a circle. It is always directed toward the center of the turning circle along a radius of the circle. Centrifugal force is force you seem to feel when you are in an automobile that is turning. As the car turns the corner, you tend to go straight because of your inertia. When the door pushes on you, causing you to go around the corner, it feels as if this force is a reaction force to an outward force on you.


8. Explain why in a skyscraper the center of gravity is lower than the center of mass, even though each level has the same mass.

ANS: Although each floor in a skyscraper has the same mass, gravity is very slightly lower at the top of the skyscraper than at the bottom. Therefore, the top half of the building has slightly less weight than the bottom half, even though both halves of the building have the same mass. This makes the center of gravity slightly lower than the center of mass.


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Chapter 7: Temperature, Energy and Matter—Multiple Choice Bank

MULTIPLE CHOICE

1. A substance with the same composition throughout containing two or more different kinds of elements chemically joined is known as a(n):a. atom.b. mixture.c. compound.d. element.


2. The smallest particle of an element that retains the chemical identity of the element is a(n):a. compound.b. atom.c. molecule.d. mixture.


3. A single atom has a diameter of about ____ meters:a. 1 × 1010

b. 1 × 100

c. 1 × 10-10

d. 1 × 10-1000


4. Of the following, the one that would be considered a mixture is:a. fruit salad.b. oxygen gas.c. table salt (sodium chloride).d. distilled water.


5. The average random kinetic energy of atoms or molecules within an object is a measure of the object’s:a. heat.b. temperature.c. thermal energy.d. specific heat.


6. The temperature at which molecules in a substance have the lowest amount of energy possible is:a. 0ºCb. 273ºCc. -300ºFd. 0 K


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7. Intermolecular forces between molecules of a substance are strongest when the material is a:a. solid.b. liquid.c. gas.d. plasma.


8. A temperature of 11ºC is equivalent to:a. 11ºF.b. 11 K.c. 284ºF.d. 284 K.


9. A temperature of 54ºF measures a temperature of about:a. 12ºC.b. 12 K.c. 327 K.d. -219 K.


10. A temperature of 87 K is nearly equivalent to:a. 87ºF.b. 360ºF.c. 360ºC.d. -303ºF.


11. The smallest change of temperature is represented by:a. one Celsius degree.b. one Kelvin.c. one Fahrenheit degree.d. either one Kelvin or one Celsius degree.


12. The property that describes the amount of heat required to raise the temperature of 1 kilogram of a substance 1ºC is its:a. thermal conductivity.b. specific heat.c. temperature variation.d. thermal energy.


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13. According to the chart below, the material requiring the most energy to raise its temperature from 20ºC to 40ºC is:

Material Specific heat (J/kgºC)

water 4,184aluminum 900

steel 470silver 235

oil 1,900concrete 880

glass 800gold 129

wood 2,500

a. water.b. gold.c. oil.d. wood.


14. The flow of thermal energy is called:a. temperature.b. specific heat.c. heat.d. thermal equilibrium.


15. The sum of all the kinetic energy of the atoms or molecules measures the object’s:a. specific heat.b. temperature.c. thermal energy.d. thermal conductivity.


16. Of the following, the greatest amount of thermal energy would be contained in:a. an ice cube.b. a room full of air at 100ºC.c. a cup of hot chocolate.d. the North Atlantic Ocean.


17. The largest unit for measuring heat is the:a. Celsius degree.b. Fahrenheit degree.c. British thermal unit.d. calorie.


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18. The specific heat of steel is 470 J/kgºC. The amount of heat needed to raise the temperature of 1.4 kilograms of steel from 12ºC to 20ºC is about ____ joules.a. 658b. 5,260c. 7,900d. 13,200


19. The specific heat of oil is 1,900 J/kgºC. If 12,000 joules of heat is added to 2 kilograms of oil at 30ºC its temperature will become ____ºC.a. 0.11b. 3.2c. 33.2d. 95


20. The graph represents the temperature changes that occur as a gas changes from a temperature of 200ºC to a solid at 20ºC:

If the 1.0-kilogram sample of gas loses heat at a constant rate of 2.0 joules per minute, the phase of the substance with the highest specific heat is:a. solid.b. liquid.c. gas.d. Cannot be determined from the graph


21. Air spaces between the feathers of a down-filled coat cause the coat to be a good thermal:a. convector.b. conductor.c. radiator.d. insulator.


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22. In nature, heat will always flow from a:a. cold object to the warm object.b. small object to the large object.c. warm object to the cold object.d. large object to the small object.


23. Heat energy from the sun is transferred to Earth by:a. radiation.b. conduction.c. convection.d. insulation.


24. Holding your hand above the flame of a candle, you will receive the most heat by means of:a. radiation.b. conduction.c. convection. d. insulation.


25. Materials that absorb radiation most effectively are also the best emitters of radiation. A wood stove for providing heat in a home will be most effective if it is:a. white.b. black.c. silver.d. red.


26. The difference you feel when holding metallic and foam containers filled with hot liquid is caused mostly by the difference in the containers’ thermal:a. radiation.b. conductivity.c. convection.d. energy.


7-94

Chapter 7: Temperature, Energy and Matter—Multi-format Bank

MODIFIED TRUE/FALSE

1. The term for smallest particle of an element that retains the chemical identity of the element is molecule. _________________________

ANS: F, atom DIF: basic REF: section 7.1

2. The temperature scale on which the freezing point of water is 32 degrees and boiling point of water is 212 degrees is the Fahrenheit scale. _________________________


3. Matter that holds its shape and does not flow is in its liquid phase. _________________________

ANS: F, solid DIF: basic REF: section 7.2

4. The sum of all the kinetic energy of the atoms or molecules of a body is called its thermal energy. _________________________


5. The quantity of heat needed to raise the temperature of 1 gram of water 1 Celsius degree of temperature is the British thermal unit. _________________________

ANS: F, calorie DIF: basic REF: section 7.3

6. Heat may be transferred between areas of a fluid due to density differences between one area and another. The movement of heat throughout the fluid by this means is called conduction. _________________________

ANS: F, convection DIF: basic REF: section 7.4

7. Heat is transferred from the sun to Earth by thermal conduction. _________________________

ANS: F, radiation DIF: basic REF: section 7.4

8. Heat transfer by conduction may NOT take place through a vacuum. _________________________


9. Materials that conduct heat poorly are called thermal conductors. _________________________

ANS: F, insulators DIF: basic REF: section 7.4

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COMPLETION

1. A pure substance that cannot be broken down into simpler substances by physical or chemical means is known as a(n) ____________________.

ANS: element DIF: basic REF: section 7.1

2. A substance that contains two or more different elements chemically joined with the same composition throughout is a ____________________.

ANS: compound DIF: basic REF: section 7.1

3. A certain brand of cough syrup contains carmel, citric acid, FD&C red #40, flavoring, glucose, glycerine, high fructose corn syrup, purified water, saccharin sodium and sodium benzoate. It is considered to be a ____________________.

ANS: mixture DIF: intermediate REF: section 7.1

4. The measure of the random kinetic energy of the atoms in an object is called _____________________.

ANS: temperature DIF: basic REF: section 7.2

5. The temperature at which molecules have their lowest possible energy is known as ____________________ (two words).

ANS: absolute zero DIF: basic REF: section 7.2

6. The temperature at which a substance changes from solid to liquid is called its ____________________ point.

ANS: melting DIF: basic REF: section 7.2

7. The Celsius and Fahrenheit scales are two commonly used temperature scales. Of these two scales, the one whose degree represents the greatest change in temperature is the ____________________ scale.

ANS: Celsius DIF: intermediate REF: section 7.2

8. The property of a substance that describes the amount of energy required to raise the temperature of one kilogram of the substance one Celsius degree is the ____________________ (two words).

ANS: specific heat DIF: basic REF: section 7.3

9. Heat is transferred to Earth from the sun by means of thermal ____________________.

ANS: radiation DIF: basic REF: section 7.4

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SHORT ANSWER

1. List three physical properties that thermometers use to detect temperatures.

ANS: Answers may vary. Correct answers include:1. color change2. volume change3. change in electrical resistance


2. The graph of temperature versus time represents the changes in the temperature of a sample of gas as it is cooled at a constant rate. What changes in the substance are occurring during the intervals from time 6 minutes to 14 minutes and from time 30 minutes to 34 minutes?

ANS: The substance is condensing (changing from gas to liquid) between 6 and 14 minutes. It is freezing (changing from liquid to solid) between 30 and 34 minutes.


3. Name the two physical properties that determine the amount of thermal energy in a material whose specific heat is known.

ANS: mass and temperature


4. Name three units commonly used for measuring heat energy. Arrange them in order from smallest to largest unit.

ANS: Answers may vary. Correct answers include any three of the following:joule, calorie, British thermal unit (Btu), Calorie


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5. Heat may be transferred by conduction, convection and radiation. By which method is it transferred most rapidly?

ANS: radiation


6. Explain in one sentence how thermal equilibrium may be established by heat flow between two objects of different temperature.

ANS: Thermal equilibrium may be established as heat flows from the body of higher temperature to one of lower temperature.


7. A thermos, a two-layered bottle, is effective in maintaining the temperature of a substance inside because a vacuum is maintained between the inside bottle and the outside container. Name the type of heat transfer the thermos is LEAST effective in preventing.

ANS: radiation


PROBLEM

1. The average body temperature for a human body is 98.6°C. Calculate the equivalent temperature on the Celsius scale.

ANS: 37ºCTc =

5

9Tf − 32Ê

ËÁÁ ˆ

¯˜ =

5

998.6 − 32( ) = 37°C


2. Room temperature is given as 20ºC. What is this temperature given in Kelvins?

ANS: 293 KTk = Tc + 273 = 20 + 273 = 293 K


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3. Convert the temperature of 233 K to the equivalent in Fahrenheit degrees.

ANS: -40ºF

First convert 233 Kelvins to Celsius:Tc = Tk − 273 = 233 − 273 = −40°CThen, convert -40ºC to Fahrenheit:Tf =

9

5Tc + 32 =

9

5−40( ) + 32 = −40°F


4. The specific heat of concrete is 880 J/kgºC). How much heat energy from the sun would be needed to raise the temperature of a 1,500-kilogram block on a concrete sidewalk from 0ºC to 20ºC?

ANS: E = mcp T2 − T1

ÊËÁÁ

ˆ¯

E = 1,500 kgÊËÁÁ

ˆ¯ 880 J/kg°CÊËÁÁ

ˆ¯ 20°C − 0°C( ) = 26,400,000 J = 2.64 × 107 joules = 2.64 × 107 joules


5. A 0.22-kilogram block of aluminum with a temperature of 320ºC is added to 1.0-kilogram of water with a temperature of 5ºC. Assuming no heat is lost to the air, what is the final temperature of the aluminum block?HINTS:You can use the equation: Energy gained by the water = Energy lost by the aluminumSpecific heat of water = 4,184 J/kgºCSpecific heat of aluminum = 900 J/kgºC

ANS: energy gained by water = energy lost by aluminum

mwcpw T2 − T1ÊËÁÁ

ˆ¯ = ma cpa T3 − T2

ÊËÁÁ

ˆ¯

1 kgÊËÁÁ

ˆ¯ 4184 J/kg°CÊËÁÁ

ˆ¯ T2 − 5°CÊËÁÁ

ˆ¯ = 0.22 kgÊ

ËÁÁˆ¯ 900 J/kg°CÊËÁÁ

ˆ¯ 320°C − T2ÊËÁÁ

ˆ¯

T2 = 19°C


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ESSAY

1. List and describe the four phases of matter. Give a common example of each.

ANS: Solid: holds it shape and does not flow; wood in a treeLiquid: holds it volume but does flow; water between 0ºC and 100ºC.Gas: flows like a liquid and will expand or contract to fill its container; airPlasma: the most abundant phase in the universe, it exists at extremely high temperatures as an ionized gas with the ability to conduct electricity; lightning


2. As water is heated from -20ºC to 20ºC, there is a period of time during which the temperature does not rise. Identify the process occurring while the temperature is not rising and explain why the temperature does not rise.

ANS: The process is melting. To melt, energy must be added so that intermolecular forces can be broken. Until all intermolecular forces are broken, the temperature will not rise. As soon as all forces are broken and all ice is changed to liquid water, the temperature will begin to rise again.


3. On a sunny day, why does the water of the ocean seem cool and the sand on the beach feel hot, yet in the evening the water feels warm and the sand cool?

ANS: The specific heat of sand is much lower than the specific heat of water. Sand heats and cools more rapidly than water. During the day the sun warms the sand quickly but does not warm the water much. At night, when the sun goes down, the sand cools quickly and feels cool to touch but the water, by comparison, seems warm.


4. Explain why the specific heat of a dense material like gold is lower than the specific heat of a less dense material like aluminum.

ANS: Specific heat is the heat needed to raise the temperature of 1 gram of a material 1ºC. Because there are fewer particles in one gram of a dense material compared to the number in a less dense material, the energy that is added to the dense material is divided between fewer particles. Since temperature measures the average kinetic energy per particle, the dense material needs to receive a smaller amount of heat energy to cause the body of dense material to rise the same amount as the less dense material.


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5. Jill and Sarah sit down together to enjoy a cup of cocoa with marshmallows. Sarah stirs her marshmallows in with a spoon made of gold. Jill stirs her cocoa using a stainless steel spoon. Sarah complains that her gold spoon is too hot to touch. Jill does not agree and thinks that Sarah is being whiney. Using your knowledge of physics, offer an excuse for Sarah.

Specific heat of gold = 129 J/kgºCSpecific heat of stainless steel = 470 J/kgºC

ANS: The specific heat of gold is 129 J/kgºC while the specific heat of steel is 470 J/kgºC. If the mass of the gold spoon is the same as the steel spoon, it will heat more than 3.5 times faster than the steel spoon. It is likely that the temperature of the gold spoon has increased to a high temperature rapidly, making the spoon too hot to handle comfortably.


6. On a warmer-than-average winter day, Tom is supposed to shovel snow from the sidewalk. Instead, he spreads black ashes from the wood stove on the snow. He claims this will clear the snow from the sidewalk. Explain why Tom may be correct.

ANS: Black objects are more effective in absorbing heat than lighter colored objects. While the white snow will tend to reflect heat, the black ashes will tend to absorb enough heat, perhaps enough to melt the snow, clearing the sidewalk.


7. Two metal chairs are located outside on a cold winter day. The temperature of both chairs are measured to be 15ºF. The seat of one chair is covered with a layer of styrofoam. The seat of the other is not. Explain why the seat without the styrofoam layer feels colder to sit on.

ANS: While both objects are at the same temperature, metal is a much better conductor of heat than styrofoam. It will conduct the heat of your body away when you sit on the chair. The styrofoam will not do so as rapidly. The plain metal chair, therefore, feels colder


8-101

Chapter 8: Physical Properties of Matter—Multiple Choice Bank

MULTIPLE CHOICE

1. Properties that can be seen through direct observation are called:a. physical properties.b. chemical properties.c. chemical reactions.d. chemical equations.


2. An example of a chemical property is the:a. rough texture of sandpaper when touched.b. tendency of water to exist as a solid at temperatures below 0ºC.c. color of a lemon.d. reaction of iron in the presence of oxygen.


3. Change that is easily reversible is classified as ____ change.a. chemical b. nuclearc. physicald. atomic


4. Density is calculated as:a. mass times volume.b. mass divided by volume.c. volume divided by mass.d. mass plus volume.


5. Density may be measured in units of:a. kilograms × meters.b. kilograms ÷ meters.c. kilograms × cubic meters.d. kilograms ÷ cubic meters.


6. The density of a material is dependent upon:a. the mass of individual atoms of the material.b. how the molecules of the material are “packed.”c. BOTH the mass of the atoms and the “packing” of the molecules.d. the product of the individual atomic masses and the space between molecules.


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7. Examples of amorphous solids include all of the following EXCEPT:a. salt.b. rubber.c. wax.d. glass.


8. The ratio of the force acting through a material and the cross-section area through which the force is carried is known as:a. strength.b. stress.c. strain.d. stretch.


9. The metric unit for stress is the:a. newton.b. kilogram.c. pascal.d. square meter.


10. The amount of stress a material can withstand when stretched or subjected to tension is called:a. elasticity.b. brittleness.c. tensile strength.d. deformation.


11. The ability to be deformed and return to the original size and shape is called:a. elasticity.b. flexibility.c. brittleness.d. tensile strength.


12. Examples of physical changes include all of the following EXCEPT:a. bending a metal bar.b. melting ice.c. dissolving sugar in water.d. burning a match.


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13. Referring to the chart below, the two objects or materials that have the same density are:

Material Density (g/cm3)Platinum 21,500Lead 11,300Steel 7,800Titanium 4,500Aluminum 2,700Glass 2,700Granite 2,600Concrete 2,300Plastic 2,000Rubber 1,200Liquid water 1,000Ice 920Oak (wood) 600Pine (wood) 440Cork 120Air (avg. room) 0.9

a. 450 grams of water and 100 grams of titanium.b. 200 grams of plastic golf tees and a plastic cube 10.0 cm on an edge.c. 10.0 grams of rubber stoppers and 20.0 cubic centimeters of oak wood.d. 1.00 cubic meters of concrete and 0.88 cubic meters of a granite statue.


14. A titanium tube in a bicycle frame has a cross-section area of 1.00 × 10-4 square meters. How much force would be required to break the tube if the rider “crashes” the bike?(tensile strength = 900 × 106 pascals)a. 1.11 × 10-13 newtons.b. 9 × 104 newtons.c. 9 × 106 newtons.d. 9 × 1010 newtons.


15. A beachball floating in a swimming pool has a mass of 0.30 kilograms and a volume of 0.15 cubic meters. The density of the floating ball is ____ kg/m3.a. 0.045b. 0.45c. 0.50d. 2.0


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16. The density of air is 0.9 kg/m3. When a balloon is inflated with air, it has a volume of 0.27 cubic meters. The mass of the air used to fill the balloon is about ____ kilogram(s).a. 0.2b. 0.3.c. 1d. 3


17. The density of a diamond is 3,500 kg/m3. If a diamond with a mass of 2 grams is dropped into a graduated cylinder containing water, the water level in the graduated cylinder will rise ____ cubic centimeters.a. 0.57b. 1.75c. 3.50d. 7.00


18. A 40-meter long steel beam in bridge has coefficient of expansion of 1.2 × 10-5 per Celsius degree. On a summer day, the temperature changes from 10ºC to 25ºC. The length of the beam will increase by ____ meters.a. 0.00018b. 0.00048c. 0.0072d. 40


19. All of the following statements concerning fluid pressure are correct EXCEPT:a. pressure exerts force on any surface touching a fluid.b. energy and pressure are not related.c. pressure is derived from the collisions between atoms and molecules.d. differences in pressure create potential energy.


20. A scientific principle states that an upward force is exerted on an object in a fluid equal to the weight of the fluid pushed aside by the object. The scientist credited for first recognizing this principle is:a. Archimedes.b. Bernoulli.c. Newton.d. Galileo.


21. The difficulty with which a fluid may be poured from a container is a measure of its:a. tensile strength.b. density.c. viscosity.d. mass.


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22. The measure of the upward force applied by a fluid on an object is called:a. density.b. buoyancy.c. weight.d. volume.


23. Characteristics that are typical of most fluids include all of the following EXCEPT fluids:a. are more dense than their solid phase.b. are less rigidly organized than their solid phase.c. exist at higher temperatures than their solid phase.d. flow when a force is applied.


24. Water is not typical of most substances in its solid phase because:a. it exists at lower temperature than its liquid phase.b. molecules are more organized than its liquid phase.c. it is less dense than its liquid phase.d. it has a crystalline structure.


25. An object has a weight of 2.5 newtons when suspended by a string attached to a spring scale.When the object, still suspended from the string, is held in a container of water without touching the sides or bottom of the container, the weight is 1.5 newtons. The buoyant force of the water is ____ newton(s).a. 1.0b. 1.7c. 3.8d. 4.0


26. All of the following statements about fluid pressure are correct EXCEPT fluid pressure:a. is measured in pascals.b. is the force per unit area.c. is transmitted in all directions.d. in a container decreases with the depth of the fluid.


27. Of the fluid characteristics named below, the one with the smallest overall effect on the energy of a fluid moving along a stream line is:a. temperature.b. height.c. speed.d. pressure.


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28. The density of water is 1,000 kgm/m3. An object with a volume of 0.1 cubic meters submerged in water experiences a buoyant force of ____ newtons.a. 100b. 980c. 1,000d. 9,800


29. The density of water is 1,000 kgm/m3. The pressure at the bottom of a swimming pool of water 2.50 meters deep is ____ N/m2.a. 400 b. 2,500c. 9,800d. 24,500


30. Tire pressure in an automobile tire is typically 210,000 N/m2. How much tire area must be in contact with road to support a 2000-kilogram vehicle?a. 0.0095 square metersb. 0.093 square metersc. 10.7 square metersd. 105 square meters


31. As the pressure on a gas at constant temperature increases, the volume decreases. This idea is stated in a scientific principle known as ____ law.a. Boyle’sb. Charles’c. Guy-Lussac’sd. Kelvin’s


32. The gas that appears in greatest quantity in the atmosphere of Earth is:a. argon.b. carbon dioxide.c. nitrogen.d. oxygen.


33. “The volume of a gas increases with increasing temperature” is a statement of ____ law.a. Boyle’sb. Charles’c. Guy-Lussac’sd. Kelvin’s


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34. In the 200-cubic centimeter chamber of a bicycle pump the pressure is 104 kilopascals. As the handle is pushed down on the pump, the volume is reduced to 50 cubic centimeters. The pressure in the chamber of the pump is ____ kilopascals.a. 26b. 52c. 208d. 416


35. A balloon is filled with 500 cubic centimeters of air at 27ºC. To what temperature must the air be changed to reduce the volume of the balloon to 250 cubic centimeters?a. 13.5ºCb. 54ºCc. -123ºCd. 150ºC


8-108

Chapter 8: Physical Properties of Matter—Multi-format Bank

MODIFIED TRUE/FALSE

1. “The weight of an object immersed in a fluid will be reduced by the weight of the fluid displaced by the object” is a statement of Bernoulli’s principle. _________________________

ANS: F, Archimedes DIF: basic REF: section 8.2

2. The property of a fluid that indicates the amount of friction within a fluid is pressure. _________________________

ANS: F, viscosity DIF: basic REF: section 8.2

3. “As the pressure on a fluid increases, the volume of the fluid decreases.” This is a statement of Charles’ law. _________________________

ANS: F, Boyle’s DIF: basic REF: section 8.3

4. Absolute zero, the lowest temperature possible, can be given as minus 273ºC. _________________________


5. The most abundant gas in Earth’s atmosphere is oxygen. _________________________

ANS: F, nitrogen DIF: basic REF: section 8.3

COMPLETION

1. Properties that can be observed only when one substance is changed into another are called ____________________ properties.

ANS: chemical DIF: basic REF: section 8.1

2. The ratio of mass to volume is known as ____________________.

ANS: density DIF: basic REF: section 8.1

3. A solid whose particles are arranged in a random way is said to a(n) ____________________ solid.

ANS: amorphous DIF: basic REF: section 8.1

4. A measure of the stress due to pulling or tension that a material can withstand before breaking is called ____________________. (two words)

ANS: tensile strength DIF: basic REF: section 8.1

5. The tendency of a solid to break or crack when a force is applied is called ____________________.

ANS: brittleness DIF: basic REF: section 8.1

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6. A number used to express the change in the length of a material caused by a change in temperature of the material is known as the ________________________________________. (four words)

ANS: coefficient of thermal expansion DIF: basic REF: section 8.1

7. A measure of the upward force a fluid exerts on an immersed body is ____________________.

ANS: buoyancy DIF: basic REF: section 8.2

8. The metric unit used for measuring pressure is the ____________________.

ANS: pascal DIF: basic REF: section 8.2

9. The total energy for a particular fluid remains constant along a streamline. This variation of the law of conservation of energy is also known as ____________________ principle.

ANS: Bernoulli’s DIF: intermediate REF: section 8.2

SHORT ANSWER

1. In general, how do the densities of solids, liquids, and gases compare?

ANS: In general, the densities of solids are the highest, those of gases are lowest, and the densities of liquids are intermediate in value.


2. Name three factors that determine the viscosity of a fluid.

ANS: Molecule size, molecule shape, and fluid temperature.


3. A cork with a volume of 500 cubic centimeters and a mass of 60 grams is floating in water. What is the weight of the water displaced by the cork?

ANS: The cork will settle in the water to a point where the weight of the water it displaces is equal to its own weight.

weight of the cork = m× g = 0.06 kg × 9.8 m/sec2 = 0.588 N

weight of the cork = weight of water displaced

weight of water displaced = 0.588 newtons


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4. If the temperature of a gas is held constant, what would happen to the volume of a gas if the pressure on the gas is increased to three times the original amount?

ANS: The volume would decrease to a third the original size.


5. Describe the effect of increasing the temperature of a gas on the pressure exerted by the gas when a constant volume is maintained.

ANS: An increase in the temperature of the gas will cause an increase in the pressure when a constant volume is maintained.


PROBLEM

1. Calculate the volume of a small iceberg with a mass of 200,000 kilograms.(density of ice = 920 kg/m3)

ANS:

volume =mass

density=

200,000 kg920 kg/m3

volume = 217 cubic meters


2. Calculate the cross-section area needed using an oak beam to support a 10,000-kilogram mass.(tensile strength of oak = 95 × 106 pascals)

ANS: weight = mass × g = 10,000 kg × 9.8 m/sec2 = 98,000 N

tensile strength =force

cross-section area

cross-section area =force

tensile strength=

98,000 N95 × 106 Pa

cross-section area = 0.00103 cubic meters


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3. A stone that weighs 6.5 newtons in air weighs only 5.0 newtons when submerged in water. What is the buoyant force exerted on the rock by the water?

ANS: 1.5 newtons

buoyant force = weight in air - weight in fluid = 6.5 N - 5.0 N = 1.5 newtons


4. Calculate the pressure at the bottom of a water-filled aquarium that is 0.40 meters deep.(density of water = 1000 kg/m3)

ANS: pressure = density × depth × g = 1,000 kg/m3 × 0.40 m× 9.8 m/sec2

pressure = 3920 pascals


5. Rita opened a 500 cubic centimeter bottle of water and drank half of it, leaving 250 cubic centimeters of air space at the top of the bottle. When she left the bottle with the cap in her car, the temperature was 20ºC. When she came back to her car later in the day the temperature had risen to 40ºC. What is the pressure of the air in the bottle?

ANS: First, convert temperatures from Celsius to Kelvin:

20°C = 293 K

40°C = 313 K

P1 is at atmospheric pressure (1 atm)

P1

T1

=P2

T2

1 atm293 K

=P2

313 K

P2 = 1.07 atmospheres


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ESSAY

1. Explain why the ability to withstand an applied force is not enough to describe the strength of a material.

ANS: Although materials may be described as strong because they can support a large load, the size and shape of the object made from a specific material will have a great effect on its ability to bear the load. Stress is the ratio of the force applied to the cross-sectional area through which the force is applied. This ratio allows for a more accurate comparison of the strength of materials.


2. Jim and his friend Bill are building a small pond on their farm by piling rocks across the channel of a stream to make a dam. If they have difficulty lifting a rock out of the water to move it to the dam, they carry the rock more easily by keeping it under the surface of the water. Explain why this works.

ANS: Since the rock is more dense than water, it will naturally tend to stay submerged under the surface. To pick the rock up completely out of the water requires a force equal to the entire weight of the rock. If the rock is lifted just enough to get it off the bottom of the stream but it still remains under the surface of the water, the buoyant force of the water will reduce the force the boys have to exert to lift the rock.


3. Describe how Newton’s third law is related to fluid pressure.

ANS: Molecules are in constant motion.As a molecule strikes the sides of its container, the wall of the container applies a force on the molecule. The molecule applies an equal and opposite force on the wall. The sum of these individual reaction forces on the area of the wall results in the pressure exerted by the fluid on its container.


4. The density of steel is 7800 kg/m3. The density of water is 1000 kg/m3. Explain how steel ships are made to float in water.

ANS: Less dense substances will float in fluids which are more dense. Solid steel has a density of 7800 kg/m3. Solid steel will not float in water. Ships that are made of steel are not solid but are mostly air. The average density of the ship is less than 1000 kg/m3, the density of water, and therefore the ship floats.


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5. While pumping up the tire of her bicycle, Kortney feels the tire and finds it warmer to touch. What is the most likely cause for the increase in the temperature of the tire?

ANS: Pressure and energy are related. When Kortney applies force on the pump she creates pressure in the cylinder. Doing work on the air in the cylinder adds energy to the air which manifests itself as heat to raise the temperature of the air.


9-114

Chapter 9: The Atom—Multiple Choice Bank

MULTIPLE CHOICE

1. This scientist published a detailed atomic theory in 1808 based on evidence he gathered through experiments with gases. His atomic theory laid the groundwork for later atomic models.a. James Chadwickb. John Daltonc. Ernest Rutherfordd. J. J. Thomson


2. A common isotope of iron has a mass number of 56. The total number of subatomic particles in the nucleus is:a. 26.b. 56.c. 30.d. 4.


3. The ____ is one kind of particle that makes up the atom and carries a positive charge.a. electronb. protonc. neutrond. plasma


4. Atoms with the same atomic number but different atomic mass are called:a. prototypes.b. isomers.c. isotopes.d. ions.


5. The atomic number is the:a. number of electrons plus the number of protons.b. number of neutrons plus the number of protons.c. number of protons in the nucleus.d. the average number of neutrons and protons for all naturally-occurring isotopes.


6. Compared to protons, electrons have:a. much smaller mass and opposite charge.b. about the same mass and opposite charge.c. much larger mass and the same charge.d. much larger mass and opposite charge.


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7. The electric charge of an atom with the same number of protons and electrons is:a. equal to the number of protons multiplied by the charge on one proton.b. equal to the number of electrons multiplied by the charge on one electron.c. equal to the number of protons plus the number of neutrons.d. zero.


8. The force that holds neutrons and protons together in the nucleus is known as:a. the electromagnetic force.b. gravity.c. the strong nuclear force.d. the weak nuclear force.


9. Protons and neutrons are found grouped together in the:a. electron cloud.b. charge.c. nucleus.d. periodic table.


10. Electrons are bound to the nucleus by:a. the electromagnetic force.b. gravity.c. the strong nuclear force.d. the weak nuclear force.


11. This scientist led a series of experiments that used high-speed positively-charged helium atoms to bombard very thin pieces of gold foil. Some of the helium atoms went straight through the foil, but a few bounced back. He used this information to hypothesize that an atom must be made of a tiny dense nucleus surrounded by a region of mostly empty space.a. James Chadwickb. John Daltonc. Ernest Rutherfordd. J.J. Thomson


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12. Do any of the atom diagrams below represent atoms of the same element?

a. No, they are all different elements.b. Yes, atom A and atom B are the same element.c. Yes, all of the atoms are the same element.d. Yes, atom A and atom C are the same element.


13. Which of the following is a TRUE statement about atoms?a. All atoms of the same element have the same number of electrons, protons, and neutrons.b. Atoms of different elements may have the same number of protons in the nucleus.c. All atoms of the same element have the same number of electrons and protons but may

have different numbers of neutrons.d. The number of neutrons is equal to the number of protons.


14. Which of the following statements about two isotopes of the same element is FALSE?a. The number of neutrons may be different between the two isotopes.b. One isotope might be radioactive while the other isotope might be stable.c. One isotope might have a larger mass than another isotope.d. The number of protons might be different between the two isotopes.


15. The element chlorine has two stable isotopes, Cl35 and Cl37. About 3 of every 4 chlorine atoms found on Earth are Cl35, and the remainder are Cl37. The average atomic mass of chlorine is closest to ____ amu.a. 35.0b. 35.5c. 36.0d. 36.5


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The periodic table notation for carbon-13 (C13) is shown below.

Figure 9-1A

16. Referring to Figure 9-1A, how many protons, electrons, and neutrons does carbon-13 have?a. 6, 7, 13b. 6, 6, 7c. 7, 6, 13d. 7, 7, 13


17. Referring to Figure 9-1A, what is the mass number for carbon-13?a. 6b. 7c. 12d. 13


18. The periodic table notation for silicon (Si ) is shown below.

An atom of silicon has how many electrons?a. 14b. 7c. 28d. Cannot be determined with the information given.


19. All of the following are true for valence electrons EXCEPT:a. valence electrons are in the highest energy level.b. valence electrons determine almost all the properties of an element.c. atoms may share or trade valence electrons.d. each element in the periodic table has a different number of valence electrons.


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20. The vertical columns of the periodic table are:a. periods.b. groups.c. halogens.d. isotopes.


21. A way of organizing the elements based on their chemical properties is the:a. energy level.b. periodic table.c. nucleus.d. isotope.


22. Most of the elements in the periodic table can be described as:a. metals.b. nonmetals.c. metalloids.d. halogens.


23. The noble gases such as helium and xenon do not form chemical bonds with other elements because they:a. have completely filled energy levels.b. are chemically unstable.c. are unusually large atoms.d. have been around longest on the earth.


24. Which of the following statements about energy levels is TRUE?a. An energy level is a region in the electron cloud with a specific electron energy.b. All energy levels must hold the same number of electrons.c. The farther away an energy level is from the nucleus, the less energy it possesses.d. Partially filled energy levels are more stable than completely filled energy levels.


25. A group of students use a spectrometer to analyze three light sources. Different bright, vertical lines appear on the spectrometer scale as the light from each source enters the spectrometer. Each light source shows a different spectral pattern because:a. all three light sources contain the same elements.b. there are different elements in each light source.c. there are no elements associated with these light sources.d. all elements have the same spectral pattern.


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26. The diagram shows a spectrum:

The different colored bright lines represent:a. light of different energies.b. the diameter of atoms of different size.c. atoms that are radioactive.d. different values of the strong nuclear force.


27. A quanta is best described as:a. the smallest possible quantity of something.b. a quantity of mass equal to one atom.c. a particle of antimatter that releases enormous energy when it meets normal matter.d. the result of adding one neutron, one proton, and one electron.


28. Heisenburg’s uncertainty principle tells us that:a. the act of observing in the quantum world changes the very system you are trying to

measure.b. we are always uncertain about the future of a particle.c. atoms cannot exist with 100% probability.d. quantum theory only applies to single atoms.


29. Which of the following is evidence that electrons in atoms cannot have any amount of energy but instead are only allowed to have certain amounts of energy?a. The atomic mass is the sum of the number of protons and neutrons.b. Only specific colors of light are given off by atoms.c. All atoms of the same element have the same chemical properties.d. Radioactive elements are unstable.


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Chapter 9: The Atom—Multi-format Bank

MODIFIED TRUE/FALSE

1. Compared to electrons, protons have much larger mass and the same charge. _________________________

ANS: Foppositepositivedifferent


2. The strongest force in the universe is gravity. _________________________

ANS: Fstrong nuclear forcethe strong nuclear force


3. The size of the electron cloud most determines the size of an atom. _________________________


4. Atoms with the same atomic number but different numbers of neutrons are called prototypes. _________________________

ANS: F, isotopes DIF: basic REF: section 9.1

5. Elements with similar properties, listed in a single column on the periodic table, form what is called a group. _________________________


COMPLETION

1. Protons and neutrons are located in the tiny ____________________ at the atom’s center.

ANS: nucleus DIF: basic REF: section 9.1

2. The proton’s ____________________ is equal and opposite to the electron’s.

ANS: charge DIF: basic REF: section 9.1

3. The _________________________ (two words) is equal to the number of protons and is different for each element.

ANS: atomic number DIF: basic REF: section 9.1

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4. The _________________________ (two words) of an element is the total number of protons and neutrons in the nucleus.

ANS: mass number DIF: basic REF: section 9.1

5. The outer electrons in an atom that participate in forming chemical bonds are called ____________________ electrons.

ANS: valence DIF: basic REF: section 9.2

6. Each element emits a characteristic pattern of ____________________ (two words) when viewed through a spectrometer.

ANS: spectral lines DIF: basic REF: section 9.3

MATCHING

For the following element, match the letter with the type of information given.

1. name of element 2. symbol 3. atomic number

1. ANS: C DIF: basic REF: section 9.2 2. ANS: A DIF: basic REF: section 9.2 3. ANS: B DIF: basic REF: section 9.2

SHORT ANSWER

1. List the four forces found within atoms and rank them in order of decreasing strength.

ANS: strong nuclear force (strongest)electromagnetic forceweak forcegravity (weakest)


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2. Describe the reason the atomic mass of magnesium is listed as 24.31 amu when magnesium has 3 stable isotopes: Mg24, Mg25, and Mg26. Which isotope is the most commonly found on Earth?

ANS: Atomic mass is the average atomic mass for a sample of magnesium found on Earth. Since there are 3 stable isotopes, a sample of magnesium will contain a mixture of all 3. Since the average is 24.31 amu, there is more Mg24 than the heavier isotopes.


3. For the nucleus shown below, do the following:

A. Name the element.B. Give the mass number.C. Give the number of electrons.

ANS: A. carbonB. 13C. 6


4.

How many energy levels would be completely filled by an atom of neon (Ne)? How many electrons would be left over?

ANS: The neon atom has two filled energy levels and no electrons left over.


5. What is a quanta?

ANS: A quanta is the smallest possible quantity of something.


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6. What is the evidence that electrons in atoms are only allowed to have specific amounts of energy?

ANS: When viewed through a spectrometer, only specific colors of light are given off by atoms. These specific colors correspond to specific amounts of energy.


PROBLEM

1.

The figure shows a 4-sided dice, with the sides labeled 1 through 4. If you were to roll this dice once, what is the probability that you would roll at 3? If you rolled the dice 100 times, how many times would you expect to roll a 3?

ANS: The probability of rolling a 3 would be 1/4, or 0.25 (25%).

If you roll the dice 100 times, you would expect to roll the three: 100 × 0.25 = 25 times


ESSAY

1. Describe Ernest Rutherford’s gold foil experiment and the changes it led to in the model of the atom.

ANS: Rutherford led a series of experiments that used high-speed positively charged helium atoms to bombard very thin pieces of gold foil. Some of the helium atoms went straight through the foil, but a few bounced back, meaning they must have struck an area of high density. This led Rutherford to hypothesize that the atom must be made of a tiny dense nucleus surrounded by a region of mostly empty space.


2. Describe how electrons are involved in the formation of chemical bonds.

ANS: Atoms consist of a nucleus surrounded by negatively charged particles known as electrons. Many atoms become more stable by gaining, losing, or sharing electrons with other atoms to form compounds. The electrons in the atom’s outermost energy levels (known as valence electrons) are gained, lost, or shared to achieve a filled energy level of 8 valence electrons.


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OTHER

1. Draw dot diagrams for the following elements: xenon (Xe) has 8 valence electrons potassium (K) has 1 valence electron fluorine (F) has 7 valence electrons

ANS:


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Chapter 10: Energy Flow and Systems—Multiple Choice

MULTIPLE CHOICE

1. The efficiency of most machines is less than 100 percent. Due to friction, energy seems to be lost. While the energy is not truly lost, it does work that is not useful or is converted to ____ energy.a. thermalb. radiantc. potentiald. nuclear


2. Batteries are devices that change chemical energy to ____ energy.a. mechanicalb. radiantc. electricald. nuclear


3. Which of the following statements are TRUE about nuclear energy?a. Nuclear energy can result from splitting large atoms.b. Nuclear energy can result from combining small atoms.c. Nuclear energy is how the sun and stars make energy.d. All of the above


4. Light is a form of ____ energy.a. chemicalb. nuclearc. radiantd. thermal


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5. Talia is pedaling down a steep hill on her bicycle and wants to be able to coast up the next hill, which is 25.0 meters high, without pedaling up the hill at all.

Assuming her bicycle is 100 percent efficient, her speed would have to be at least ____ m/sec.a. 7.1b. 22.1c. 71d. 240


6. The rate at which work is done is called:a. force.b. efficiency.c. power.d. energy.


7. One watt is equivalent to one:a. newton/second.b. (kilogram-meter)/second.c. newton-meter.d. joule/second.


8. The efficiency of a machine is reduced by:a. effort.b. work output.c. mechanical advantage.d. friction.


9. Efficiency can be defined as the ratio of:a. work input to the work output.b. work output to work input.c. output force to input force.d. input force to output force.


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10. Anastas eats a chocolate chip cookie and then climbs a set of stairs. In doing so, the chemical energy from the cookie is transformed into ____ energy.a. potentialb. kineticc. both potential and kineticd. neither potential nor kinetic


11. Hiroko uses 1,200 joules of energy to lift a 200-newton crate 5 meters using a pulley system. The efficiency of the system is ____ percent.a. 12b. 17c. 50.d. 83


12. Lola applies force to the handle of a jack so that she can change the flat tire on her car. If she uses 1,250 joules of energy on a jack that is 40 percent efficient, how much energy is available to raise the car?a. 1,200 joulesb. 750 joulesc. 500 joulesd. 400 joules


13. The brakes on an automobile become hot when they are used continuously because the:a. work input is being converted to heat.b. work output is being converted to heat.c. efficiency of the brakes is nearly 100 percent.d. friction of the brakes causes an increase in the efficiency.


14. An automobile is about 15 percent efficient. For every 10 gallons of fuel used by the car, the number of gallons actually used to move the vehicle is:a. 1.5b. 5.0c. 6.7d. 10


15. The work output is 200 joules for a machine that is 80 percent efficient. The work input is ___ joules.a. 250b. 200c. 160d. 40


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16. The efficiency of a modern bicycle is 95 percent. If you exert 300 joules in pedaling a bicycle on level ground, what is the work output?a. 95 joulesb. 105 joulesc. 190 joulesd. 285 joules


17. If 40 watts of power are consumed in 20 seconds, the maximum work done is ____ joules.a. 0.5b. 2c. 5d. 800


18. The power used in doing 100 joules of work in 10 seconds is ____ watts.a. 1,000b. 100c. 10d. 0.1


19. How much energy is needed to run a 60-watt light bulb for five seconds?a. 12 joulesb. 30 joulesc. 60 joulesd. 300 joules


20. A bowler lifts her bowling ball a distance of 0.5 meters using 35 joules of energy. Her bowling ball has a mass of about ____ kilograms.a. 3b. 7c. 35d. Not enough information is given.


21. A gallon of gasoline contains chemical energy. If you pour a gallon of gasoline into your car, you could drive for about 20 miles on the highway (about 20 minutes). You could choose instead to run a lawn mower for an hour with one gallon of gasoline. If the gasoline in either situation were to come in contact with a fire, the entire gallon would burn in less than a minute. Which reaction has the most power?a. Burning the gasoline in the carb. Burning the gasoline in a firec. Burning the gasoline in the lawn mowerd. They are equal because the gasoline has the same chemical potential energy in each case.


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22. The ratio representing power includes all of the following EXCEPT:a. work ÷ time.b. force × velocity.c. (force × distance) ÷ time.d. force × distance.


23. Appliances are described by the rate at which they use energy. These manufacturer ratings are called ____ ratings.a. forceb. workc. powerd. efficiency


24. At each level in the energy pyramid, the amount of usable energy:a. increases.b. decreases.c. can increase or decrease.d. remains the same.


25. The organisms at the bottom of the food chain are:a. herbivores.b. decomposers.c. carnivores.d. producers.


26. Which of the following is an example of a decomposer?a. Snailb. Hawkc. Moused. Earthworm


27. Where does the energy used to drive the water cycle come from?a. Geothermal heatb. The sunc. Aird. Wind


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28. When the total energy of a system remains the same over time, the system is in:a. steady state.b. cycle.c. conversion.d. transmission.


29. If a 900-watt toaster were rated in horsepower, its rating would be about ____ horsepower.a. 0.830b. 1.21c. 828d. 1,210


30. An incandescent light bulb uses 100 joules of electrical energy every second. Due to heat loss, the energy available to light the room is reduced to 6 joules per second. The efficiency of the light bulb is ____ percent.a. 6b. 16c. 60d. 106


31. Calculate the overall efficiency of a device that uses two different processes with efficiencies of 80 percent and 50 percent.a. 1.6 percentb. 40 percentc. 63 percentd. 130 percent


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Chapter 10: Energy Flows and Systems—Multi-format Bank

MODIFIED TRUE/FALSE

1. Kinetic and potential energy are both forms of chemical energy. ______________________________

ANS: F, mechanical energy DIF: basic REF: section 10.1

2. Radiant energy is made up of electromagnetic waves. ______________________________


3. The heat released by a burning candle is an example of thermal energy. ______________________________


4. Another name for the law of conservation of energy is the first law of thermodynamics. ______________________________


5. Open system means there is a balance between energy in and energy out so that the total energy remains the same. ______________________________

ANS: F, Steady state DIF: basic REF: section 10.3

6. A carnivore is a way of describing the flow of energy between living things. ______________________________

ANS: F, food chain DIF: basic REF: section 10.3

COMPLETION

1. The rate at which work is done is called ____________________.

ANS: power DIF: basic REF: section 10.2

2. A unit of power equivalent to 746 watts is one ____________________.

ANS: horsepower DIF: basic REF: section 10.2

3. The rate at which an appliance uses energy is indicated as the appliance’s ____________________. (two words)

ANS: power rating DIF: basic REF: section 10.3

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SHORT ANSWER

1. While sitting next to a campfire, Anya noticed several different forms of energy being transformed from the potential chemical energy of the wood. Name two of the forms of energy she noticed.

ANS: Answers will vary. Correct answers include:Thermal energy (or heat)Radiant energy (or light)Sound energy


2. What is the basic source for all energy in the universe? Explain why.

ANS: Nuclear energy because that is how the stars and sun make energy.


3. You and a friend carry bundles of shingles up a ladder to the roof. In 10 minutes, your friend carries 10 bundles to the roof. You carry 10 bundles to the roof but take 20 minutes to do it. How does your power compare to your friend’s power?

ANS: You are half as powerful.


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PROBLEM

1. Benjamin, who weighs 500 newtons, and Andrei, who weighs 600 newtons, are standing at the bottom of a flight of stairs that is 4 meters high. Benjamin runs up the stairs in 5 seconds. Andrei runs up the same stairs in 6 seconds. Compare the work done and the power generated by each boy’s run up the stairs. Support your answer by showing calculations for each quantity.a. Who does more work?b. Who is more powerful?

ANS: a. Andrei does more work. He does 2,400 joules of work:

work = force × distance = 600 N × 4 m = 2,400 JBenjamin does only 2,000 joules of work:work = force × distance = = 500 N × 4 m = 2,000 J

b. The boys generate the same amount of power:power = work ÷ timeFor Andrei:power = 2,400 J ÷ 6 sec = 400 wattsFor Benjamin:power = 2,000 J ÷ 5 sec = 400 watts


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2. Gerry, who weighs 500 newtons, is late for class. It takes her 7.5 seconds to run up two flights of stairs, a total height of 8.0 meters.

How much power does Gerry expend in her run upstairs?

ANS:

power =worktime

=force( ) × distance( )

time

=500 newtons( ) × 8.0 meters( )

7.5 seconds

= 533 watts


3. An automobile uses 75,000 joules of chemical energy from gasoline to produce 10,000 joules of useful output energy. How much energy is lost to the system, and where did that energy go?

ANS: input power – output power = amount lost to the system75,000 W – 10,000 W = 65,000 watts lost to the system

This energy is converted to waste heat, friction, idling, and accessories. The energy is transformed into unusable forms of energy.


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4. Calculate the efficiency for a machine that requires 400 joules of input energy to produce 300 joules of useful output work.

ANS:


× 100 =300 J400 J

× 100 = 75%


5. Brooke uses 150 newtons of force to push a heavy box 4 meters in 10 seconds. How powerful is Brooke?

ANS: work = force × distance

power =worktime

=force × distance

time=

150 N × 4 m10 sec

= 60 watts


6. A baseball player stops a 0.15-kilogram baseball thrown at a speed of 50 m/sec in a distance of 0.1 meters. What force is required to do this?

ANS: force = 1,875 N

The work done to reduce the speed of the baseball to zero must equal the kinetic energy of the ball: work = kinetic energy.

work = force × distance = force × 0.1 m( )

kinetic energy =12

mv2 =12

0.15 kgÊËÁÁ

ˆ¯ 50 m/sec( ) 2 = 187.5 kg-m2 / sec2

work = kinetic energy

force × 0.1 m( ) = 187.5 kg-m2 / sec2

force =187.5 kg-m2 / sec2

0.1 m= 1875 N


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7. A construction worker uses a rope and pulley system to lift 2,000 newtons of lumber from the ground to a waiting helper on the second floor, 4 meters from the ground. To do this, she applies a 200-newton force on the rope of the rope and pulley. She pulls 60 meters of rope through the pulley before the load is lifted to the second floor. Based upon the information given, calculate the following for this rope and pulley:a. work inputb. work outputc. efficiency

ANS: a. work input = force × distance = 200 newtons × 60 meters = 12,000 joulesb. work output = force × distance = 2,000 newtons × 4 meters = 8,000 joulesc. efficiency = work output ÷ work input × 100% = (8,000 joules ÷ 12,000 joules) × 100% = 67%


8. 1,000 joules of work is put into a device that has two processes. The first process is 90% efficient, and the second process is 50% efficient. How much useful output work will be produced by this device?

ANS:


work output = efficiency × work input

work output (process 1) = 0.9 × 1,000 J = 900 J

The work input for process 2 is the work output from process 1:work output (process 2) = 0.5 × 900 J = 450 J


ESSAY

1. In a steady state food chain of living things, explain why you would find more herbivores than carnivores.

ANS: You would find more herbivores than carnivores because it takes many herbivores to support one carnivore. A single carnivore can only get its energy by eating herbivores or carnivores. As you proceed up through the levels of a food chain, a significant amount of energy is lost at each level. This means that the nutritional energy available to carnivores is less than the energy available to herbivores. There is simply less energy available to sustain as many carnivores as herbivores.


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OTHER

1. Illustrate the water cycle using the terms condensation, evaporation, groundwater, rivers, and precipitation. Show the source of energy used to drive the water cycle.

ANS: Answers will vary. Each student’s illustration should support the following text: Radiant energy from the sun is absorbed by water. Some water evaporates into the air, carrying energy from the warm water into the atmosphere. The water vapor goes up into the atmosphere and cools, releasing its energy to the air. The cool water condenses into droplets as rain (precipitation), which falls back to the ground. Eventually, rainwater makes its way back to the ocean through rivers and groundwater and the cycle begins again.


2. Use a diagram to show the flow of energy through a food chain. In the diagram, include the terms carnivore, decomposer, herbivore, and producer.

ANS: Answers will vary. Students’ diagrams should demonstrate the flow of energy through a food chain. Each food chain should have at least one producer, herbivore, primary carnivore, and secondary carnivore.


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Chapter 11: Changes in Matter—Multiple Choice

MULTIPLE CHOICE

1. A chemical bond forms when atoms transfer or share:a. neutrons.b. protons.c. electrons.d. ions.


2. Which statement best explains why atoms form chemical bonds with other atoms?a. Most atoms have greater energy when they combine with other atoms.b. When atoms collide with other atoms, they bond automatically.c. Atoms are always attracted to other atoms.d. Most atoms have lower energy when they are combined with other atoms.


3. Which of the following is TRUE? Covalent bonding occurs:a. in ionic compounds like NaCl.b. when electrons are shared between two atoms.c. only when electrons are shared between two identical atoms.d. when electrons are transferred from one atom to another.


4. When an atom gains or loses electrons, it has an electrical charge. It is known as a(n):a. ion.b. free radical.c. hydrate.d. monoatomic molecule.


5. When a chemical change occurs:a. atoms are rearranged.b. the law of conservation of mass is always obeyed.c. the chemical properties of new substances are different from the ones you started with.d. All of the above


Answer the following questions about the chemical reaction for the formation of rust:Fe + O2 → Fe2O3

6. Identify the reactant(s):a. Fe and Fe2O3

b. Fe and O2

c. Fe2O3

d. O2 and Fe2O3


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7. Identify the product(s):a. Fe and Fe2O3

b. Fe and O2

c. Fe2O3

d. O2 and Fe2O3


8. Is the chemical reaction for the formation of rust balanced? If not, select the correct equation from the ones listed below.a. Yes, it is balanced.b. No, this is balanced: 2Fe + O2 → Fe2O3

c. No, this is balanced: 4Fe + 3O2 → 2Fe2O3

d. No, this is balanced: 3Fe + 2O2 → 3Fe2O3


9. Sodium forms an ionic bond with chlorine when sodium ____ an electron and chlorine ____ an electron.a. shares, sharesb. loses, gainsc. gains, losesd. loses, loses


10. What is the chemical formula for a compound that contains the aluminum ion (Al3+) and the hydroxide ion (OH-)?a. Al(OH)3

b. AlO3H3

c. AlOH3

d. None of the above


11. When you eat an apple, the process of digestion involves ____ change.a. only physicalb. only chemicalc. physical and chemicald. phase


12. In which of the following situations does water undergo a change in physical properties?a. The bathroom fills with steam when you take a hot shower.b. You pour a glass of water from the faucet.c. Water is broken down to yield H2 and O2.d. When hydrogen is used as a fuel for rockets, water is a product.


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13. Balance the following equation to demonstrate the conservation of atoms in a reaction. Choose the answer that provides the correct coefficients for each reactant and product:_____ Al2O3 → _____ Al+ _____ O2

a. (2, 4, 3)b. (4, 3, 2)c. (3, 2, 4)d. (2, 3, 4)


14. If you designed your own experiment to prove the law of conservation of mass, what conditions would be required?a. You must find the mass of the reactants before the reaction and find the mass of the

products after the reaction.b. You must find the mass of the reactants before the reaction, find the mass of the products

after the reaction, AND perform the reaction in a closed system.c. You must choose a combustion reaction.d. You must use mercury because the law applies only to mercury.


15. What would be the most likely product(s) of the following reaction?H2 + O2 → _____a. H3 + O3

b. H2Oc. O3H3

d. No reaction would occur.


16. When you activate an instant cold pack, water mixes with a chemical and the pack gets very cold. This is an example of a(n):a. endothermic reaction.b. exothermic reaction.c. combustion reaction.d. a physical change.


17. The compound CaCl2 contains which of the following ions?a. Ca+ and Cl-

b. Ca2+ and Cl-

c. Ca4+ and Cl2-

d. Ca2+ and Cl4-


18. The atomic mass number for the radioisotope carbon-13 is:a. 6.b. 7.c. 12.d. 13.


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19. When an unstable isotope undergoes alpha decay, it is gives off:a. an electron.b. two protons and two neutrons.c. high energy electromagnetic radiation.d. a hydrogen atom.


20. Which of the following statements is true of gamma radiation?a. It can be harmful to living things.b. The nucleus lowers its energy.c. It requires heavy shielding. d. All of the above.


21. Which type of radioactivity leaves the atomic number unchanged?a. Alpha decayb. Beta decayc. Gamma decayd. Fission


22. The half-life is best described as the time it takes for:a. an atom to rotate halfway around.b. 50 percent of a radioactive element to decay into something else.c. each atom of a radioactive element to decay halfway.d. a nuclear fission reaction to split a nucleus in half.


23. Radiation is harmful to living things when it:a. moves at the speed of light.b. has enough energy to break chemical bonds.c. contains any infrared rays.d. is created by nuclear processes instead of chemical processes.


24. A fission reaction:a. breaks a nucleus up into smaller pieces.b. combines light nuclei to make heavier nuclei.c. is any reaction involving an isotope of uranium.d. releases only alpha particles and gamma rays.


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25. Bromine-82 is used as a tracer for organic materials in environmental studies. Its half-life is 36 hours. If you start out with 10 grams of Br-82, how long will it take for there to be 5 grams of Br-82 remaining?a. 10 hoursb. 18 hoursc. 36 hoursd. 52 hours


26. Which kind of reaction do nuclear power plants currently use to generate electricity?a. Fusionb. Fissionc. Chemicald. Hydro-powered


27. A nuclear chain reaction can occur when:a. one atom of uranium hits another atom of uranium and causes it to split apart.b. fusion reactions produce helium.c. an isotope gives off alpha decay.d. a fission reaction releases enough neutrons to trigger more fission reactions.


Figure 11-1A

28. Using Figure 11-1A as a reference, which of the following nuclear reactions is an example of a fusion reaction?a. helium-4 and carbon-12b. uranium-235 and strontium-135c. radium-228 and actinium-228d. radon-220 and polonium-216


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29. Using Figure 11-1A as a reference, which of the following is an example of a fission reaction?a. helium-4 and carbon-12b. carbon-12 and carbon-12c. radium-228 and actinium-228d. carbon-12 and magnesium-24


30. An amount of sodium-25 decreases to one-fourth its original amount in 2 minutes. What is the half-life of this radioisotope?a. 4 minutesb. 2 minutesc. 1 minuted. 30 seconds


31. Which of the following nuclear reactions is an example of alpha decay?a. carbon-14 to nitrogen-14b. carbon-12 to carbon-12c. uranium-234 to thorium-230d. cesium-137 to barium-137


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Chapter 11: Changes in Matter—Multi-format Bank

MODIFIED TRUE/FALSE

1. A bond between atoms in which electrons are shared is called a covalent bond. ______________________________


2. Combustion is a natural process that removes carbon dioxide from the atmosphere. ______________________________

ANS: F, Photosynthesis DIF: basic REF: section 11.2

3. The product is the substances formed as the result of a chemical reaction. ______________________________


4. Melting ice is an example of a chemical change. ______________________________

ANS: F, physical change DIF: intermediate REF: section 11.2

COMPLETION

1. Atoms that either gain or lose an electron become ____________________.

ANS: ions DIF: basic REF: section 11.1

2. In a chemical reaction, the energy needed to break chemical bonds in the reactants is called the ____________________ (two words).

ANS: activation energy DIF: basic REF: section 11.2

3. A chemical reaction that gets hot is ____________________.

ANS: exothermic DIF: basic REF: section 11.2

4. A nucleus is ____________________ if it is unstable and spontaneously emits energy or particles.

ANS: radioactive DIF: basic REF: section 11.3

5. A nuclear reaction in which the nucleus emits two protons and two neutrons is called ____________________ decay.

ANS: alpha DIF: basic REF: section 11.3

6. A(n) ____________________ reaction is a type of nuclear reaction in which light nuclei are combined to create heavier nuclei.

ANS: fusion DIF: basic REF: section 11.3

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7. A(n) ____________________ (two words) occurs when neutrons released from the fission of one nucleus trigger fission in other nuclei.

ANS: chain reaction DIF: basic REF: section 11.3

8. A nuclear reaction in which a neutron is transformed into a proton and an electron is called ____________________ decay.

ANS: beta DIF: basic REF: section 11.3

SHORT ANSWER

1. For the following antacid reaction, list the reactants and the products:2HCl + CaCO3 → CaCl2 + CO2 + H2O

ANS: The reactants are HCl and CaCO3; the products are CaCl2, CO2, and H2O.


Answer the following questions based on the balanced combustion reaction given below.C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

2. Based on the information given in the chemical equation, what temperature change would you expect in the reaction? Why would you expect this?

ANS: The temperature of the reaction will increase because energy is released.


3. Is this an endothermic or exothermic reaction?

ANS: exothermic


4. Write the balanced equation for the following reaction:The fuel used in gas grills is called propane (C3H8). Propane reacts with oxygen gas (O2) found in the air to produce carbon dioxide gas (CO2) and water vapor (H2O).

ANS: C3H8 + 5O2 → 3CO2 + 4H2O


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5. What radioactive technique is used to determine the age of fossils?

ANS: Radioactive C-14 carbon dating is used to determine the age of fossils.


6. Give one example of harmful radiation and 1 example of helpful radiation.

ANS: Answers may vary. Correct answers include:Ultraviolet light from the sun is harmful. Light from the sun is helpful.Intense X rays are harmful, but medical X rays can be helpful.


7. List at least three everyday uses for nuclear reactions.

ANS: Answers may vary. Correct answers include:radioactive tracers, sterilization of packaged food, energy from the sun, X rays, radiation therapy for cancer, smoke detectors, and luminescent hands and face of some analog watches


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Figure 11-1

8. Based on Figure 11-1, what is the half-life of sodium-25?

ANS: 1.0 minute


9. Based on Figure 11-1, at time 0, what percent of the radioactive nuclei are present?

ANS: 100 percent


10. Based on Figure 11-1, after 2 minutes, what percent of the original nuclei are still radioactive?

ANS: 25 percent


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11. Explain what is meant by the statement “radioactive decay depends on chance.”

ANS: It is not possible to predict when any specific radioactive atom will decay. We can only give the probability (chance) that an atom will decay in a given interval of time. For example, there is a 50 percent chance the atom will decay in the first ten minutes.


PROBLEM

1. Carbon-14 (C14) decays into nitrogen-14 (N14) with a half life of 5,700 years. How many years would it take a sample of C14 to decay so much that only 1/8 of the atoms were still C14?

ANS: 1

8=

1

2×

1

2×

1

2= 3 half-lives = 17,100 years


ESSAY

1. Describe how electrons are involved in the formation of chemical bonds. Include in your description the difference between ionic and covalent bonds.

ANS: Atoms consist of a nucleus surrounded by negatively charged particles known as electrons. Many atoms become more stable by gaining, losing, or sharing valence electrons with other atoms to form compounds. When electrons are lost or gained, the atom becomes charged. This charge causes the atom to be attracted to atoms with an opposing charge. This kind of attraction usually results in the formation of an ionic bond. When electrons are shared between two atoms, a covalent bond is formed.


2. When you mix baking soda and vinegar, the mixture bubbles violently and the temperature drops. Is this a chemical change or a physical change? Provide evidence to support your answer.

ANS: When baking soda and vinegar are combined, a chemical change is observed. Fizzing and bubbling are an indication that a new gas is being formed. The change in temperature is an indication that new chemical bonds are being formed.


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3. Describe how photosynthesis and respiration are almost reverse reactions.

ANS: Photosynthesis is a natural reaction that takes energy from sunlight and stores it as chemical bonds in molecules of glucose. Carbon dioxide and water are used up and glucose and oxygen are produced.

Respiration is a series of reactions that animals use to produce energy from eating plants by breaking down glucose molecules. Glucose and oxygen are used up and carbon dioxide is produced.

Together, these two reactions create a balance on Earth between plants, animals, and the carbon dioxide and oxygen in the atmosphere.


4. The mass of an iron bolt was 5.4 grams when it was manufactured. After being bolted to an outdoor structure for several months, the mass of the bolt was found to have increased by 0.2 grams. Given the following balanced equation for the reaction, does this example support the law of conservation of mass? Why or why not?4Fe +3 O2 → 2Fe2O3

ANS: Yes, the law of conservation of mass is upheld because we can account for the gain in mass. The iron bolt is being oxidized (rusting). The law of conservation of mass states that the total mass of the reactants is equal to the total mass of the products. In this case, oxygen and iron are the reactants, and they combine to produce rust (Fe2O3). Some of the original iron remains unreacted as well.


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Chapter 12: Relativity—Multiple Choice Bank

MULTIPLE CHOICE

1. The energy released in a nuclear reaction comes from:a. the conversion of mass to energy.b. breaking chemical bonds between atoms.c. heat produced by the rapid motion of protons and neutrons.d. atoms rapidly changing phase from solid to liquid.


2. The speed of light is:a. always constant.b. 300,000,000 m/sec.c. represented by the symbol c.d. All of the above


3. What happens when antimatter meets an equal amount of normal matter?a. The antimatter and matter are converted to pure energy.b. The antimatter and matter are converted to radioactive material.c. The big bang is created.d. A black hole is created.


4. Einstein’s formula, E = mc2, tells us that:a. the speed of light is a constant.b. matter and energy can be turned into each other.c. chemical reactions release energy.d. forces move at the speed of light.


5. In Einstein’s formula, E = mc2, the symbol E stands for:a. Einstein.b. energy.c. exothermic.d. endothermic.


6. The antimatter twin of an electron is:a. positively charged.b. negatively charged.c. neutral.d. None of the above


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7. If you converted 1 kilogram of matter completely into energy, how much energy would you create?a. 3 × 108 joulesb. 1 × 1016 joulesc. 3 × 1016 joulesd. 9 × 1016 joules


8. Which of the following travels the fastest in a vacuum?a. Lightb. Gravityc. Radio wavesd. All of the above; they all travel at the same speed.


9. When an object approaches the speed of light, its mass:a. increases.b. decreases.c. stays the same.d. Not enough information given.


Use the diagram and information to answer the questions below:

Figure 12-1A

Jupiter is 7.8 × 108 kilometers (780,000,000 km) from the sun. The speed of light is 3 × 105 kilometers/sec (300,000 km/sec).

10. Referencing Figure 12-1A, it takes ____ seconds for sunlight to travel to Jupiter.a. 3.8 × 10-4

b. 1.0c. 2,600d. 2.3 × 1014


11. Referencing Figure 12-1A, if the sun were to vanish, it would take ____ seconds before an observer on Jupiter would see the sun go out.a. 0.00038b. 1.0c. 2,600 d. 2.3 × 1014


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12. Referencing Figure 12-1A, if the sun were to vanish, it would take ____ seconds before Jupiter would fly out of orbit because the gravitational force between Jupiter and the sun disappears.a. 0.00038b. 1.0c. 2,600 d. 2.3 × 1014


13. According to the theory of special relativity, a moving clock:a. will not run.b. runs faster.c. runs in reverse.d. runs slower.


14. Black holes:a. have such strong gravity that no light can escape.b. are observable by refracting telescopes.c. are the cause of the big bang.d. All of the above


15. Time moves more slowly for an object in motion than for one at rest. This effect is known as:a. special relativity.b. time dilation.c. big bang.d. reference frame.


16. Which of the following are effects of special relativity?a. Time runs slower for moving objects.b. Mass increases as an object gets closer to the speed of light.c. Space gets smaller for an object moving near the speed of light.d. All of the above


17. An unexpected result of Michelson and Morley’s experiment in measuring the speed of light is that the speed of light:a. is always the same, independent of your relative motion.b. increases as it travels away from you.c. decreases as it travels away from you.d. would appear to be zero if you traveled alongside it at the same speed.


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18. A 25-year-old astronaut leaves Earth and travels for 20 years (as measured on Earth) at close to the speed of light. The biological age of the astronaut when he returned to Earth at the end of the 20 years would be ____ years.a. less than 45b. 45c. greater than 45d. Not enough information given


19. Which of the following best describes what is “relative” in the theories of relativity?a. Measurements of time and motion change relative to their frame of reference.b. Everything is relative.c. The speed of light is relative.d. Antimatter twins are relatives.


20. What is the big bang?a. The hugely powerful explosion that created the universeb. The center of the Milky Way Galaxyc. Matter that travels faster than the speed of lightd. The nuclear reaction produced by the sun


21. Because the universe is expanding, we can infer that it must have been ____ at one time.a. slowerb. smallerc. largerd. faster


22. Einstein’s theory of general relativity describes gravity as an effect created by:a. the Milky Way Galaxy.b. a black hole.c. the curvature of space and time.d. the big bang.


23. According to Einstein’s principle of equivalence, gravity is equivalent to:a. velocity.b. acceleration.c. net force.d. energy.


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24. In a nuclear reactor, 6.3 × 1013 joules of energy are produced in a fission reaction splitting uranium. The mass of uranium converted to energy is ____ kilograms.a. 0.0007b. 1.0c. 210,000d. 1.89 × 1022

ANS: AE = mc2

m =Ec2 =

6.3 × 1013

3 × 108ÊËÁÁÁ

ˆ¯˜

2 = 0.0007


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Chapter 12: Relativity—Multi-format Bank

MODIFIED TRUE/FALSE

1. Every particle of matter has an antimatter twin. ______________________________


2. The speed of light is equal to 100,000 meters per second. ______________________________

ANS: F300,000,0003 × 108


3. Time moves more quickly for an object in motion than for one at rest. ______________________________

ANS: F, slowly DIF: intermediate REF: section 12.2

4. The hugely powerful explosion that created the universe is called the black hole. ______________________________

ANS: F, big bang DIF: basic REF: section 12.3

5. The principle of equivalence states that gravity is equivalent to acceleration. ______________________________

ANS: T DIF: intermediate REF: section 12.3

COMPLETION

1. The c in Einstein’s formula (E = mc2) stands for the _________________________ (three words).

ANS: speed of light DIF: basic REF: section 12.1

2. The antimatter twin of a proton would have a ____________________ charge.

ANS: negative DIF: basic REF: section 12.1

3. The effect of time slowing down close to the speed of light is known as _________________________ (two words).

ANS: time dilation DIF: basic REF: section 12.2

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4. According to the big bang, the universe is ________________________.

ANS: expandinggetting biggergetting largerincreasing


SHORT ANSWER

1. Where does the energy released by a nuclear reaction come from?

ANS: The energy released by a nuclear reaction comes from the conversion of mass to energy. The amount of energy can be calculated using Einstein’s formula, E = mc2.


2. What happens when antimatter meets an equal amount of normal matter?

ANS: The antimatter and matter are converted to pure energy.


3. Which travels the fastest: light, gravity, or radio waves?

ANS: They all travel at the same speed, the speed of light, which is equal to 300,000,000 m/sec.


4. Energy is produced by the sun in fusion reactions. What does this say about the mass of the sun?

ANS: As energy is produced by the sun, the mass of the sun decreases according to Einstein’s formula, E = mc2.


5. What is “relative” about the theory of special relativity?

ANS: Motion is relative with respect to a frame of reference.


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6. Explain what the variables in the equation E = mc2 represent and the meaning of the equation itself.

ANS: E stands for energy, m stands for mass, and c is the speed of light. The equation says that mass and energy are equivalent and that a small amount of mass represents a tremendous amount of energy because c is a very large number.


You are traveling in a spaceship at 500,000 m/sec. Your friend is standing on the ground observing as you travel by. Use this scenario to answer the following questions:

7. If you were to throw a ball at 10 m/sec in the same direction the rocketship is traveling, what speed would your friend on the ground see the ball traveling? What speed would you see the ball traveling from inside the rocketship?

ANS: An observer on the ground would see the ball traveling at:500,000 m/sec +10 m/sec = 500,010 m/sec

You would see the ball traveling at 10 m/sec on the rocketship.


8. If you were to shine a light in the same direction the rocketship is traveling, what speed would your friend on the ground see the light traveling? What speed would you see the light traveling from inside the rocketship?

ANS: You and your friend would both see the light traveling at 300,000,000 m/sec (or c). According to the theory of special relativity, the speed of light is constant to all observers in all reference frames.


9. If you were holding a meterstick in the rocketship, how would the meterstick look to your friend on the ground? How would the meterstick look to you from inside the rocketship?

ANS: Your friend would see the meterstick as shorter than a meter because length contracts for a moving frame of reference. Inside the rocketship, you would see the meterstick as a meter long.


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PROBLEM

1. If 0.001 kilograms of matter were completely converted into energy, how much energy would be created?

ANS:

E = mc2 = 0.001 kgÊËÁÁ

ˆ¯ 3× 108 m/secÊËÁÁÁ

ˆ¯˜

2= 9 × 1013 joules


2. A nuclear power plant produces 1,000,000,000 joules of energy each second. How much mass is converted to energy each second?

ANS: E = mc2

m =Ec2 =

1 × 109 J

3 × 108 m/secÊËÁÁÁ

ˆ¯˜

2 = 1.1 × 10−8 kilograms


3. If 1 microgram (1 × 10-9 kilograms) of material is completely converted to pure energy, how long could the energy produced operate a 100-watt lightbulb?

ANS: E = mc2

E = 1× 10−9 kgÊËÁÁÁ

ˆ¯˜ 3 × 108 m/secÊËÁÁÁ

ˆ¯˜

2= 9× 107 J

P =Et

t =EP=

9 × 107 J100 W

= 9 × 105 seconds = 250 hours


13-159

Chapter 13: Electric Circuits—Multiple Choice Bank

MULTIPLE CHOICE

1. The motion of charges in wires, motors, light bulbs and other devices is best called electric:a. power.b. voltage.c. current.d. conductance.


2. A circuit diagram:a. uses symbols to represent each part of the circuit.b. can be interpreted by anyone familiar with electricity.c. makes the design of an electrical circuit easier.d. is described, in part, by each of the above statements.


3. In many circuit diagrams, any device that uses electrical energy is represented by a:a. light bulb.b. heating element.c. resistor.d. motor.


4. A circuit with a switch turned to the OFF position or a circuit with any break is called (a)n:a. closed circuit.b. short circuit.c. resistor circuit.d. open circuit.


5. A closed circuit:a. is off.b. is on.c. has a break in it.d. requires no voltage.


6. Suppose you are trying to help someone gain a better understanding of electric circuits. If you compare an electrical circuit to a system that carries water, what would the water pipes represent?a. Batteryb. Wiresc. Electromagnetd. Switch


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7. All of the following devices are used to create an open circuit EXCEPT a:a. fuse.b. battery.c. switch.d. circuit breaker.


8. In an electrical circuit, the term current refers to:a. resistance.b. potential difference.c. flowing charges.d. energy loss.


9. When you talk about a battery's voltage, you are referring to:a. how easily electric current moves through it.b. the flow of electricity through the battery.c. its ability to carry electric current.d. the difference of energy per unit of charge.


10. A device that uses chemical energy to push current in a circuit is called a:a. battery.b. voltmeter.c. ammeter.d. potentiometer.


11. Devices that can be used to measure current directly include the multimeter and the:a. potentiometer.b. ammeter.c. voltmeter.d. ohmmeter.


12. A device that protects a circuit from too much current by creating a break in the circuit is a:a. switch.b. short.c. fuse.d. resistor.


13. The energy carried by each unit of moving charge in a circuit is called:a. amperage.b. voltage.c. resistance.d. wattage.


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14. In an electrical circuit, a voltage difference:a. supplies energy to make charges flow.b. causes a short circuit.c. is the term used for rate of charge flow.d. wastes energy.


15. Which of the following makes a good analogy for a battery?a. Water pipesb. Narrow areas in water pipesc. Water faucetd. Water tower and pump


16. What should the voltmeter read (approximately)?

a. 4.5 voltsb. 1.5 voltsc. 3.375 voltsd. 3 volts


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The figure below shows four different ways to connect a meter to a circuit:

Figure 13-1A

17. The diagram in Figure 13-1A that shows a meter properly connected for measuring current through the light bulb is pictured at:a. Ab. Bc. Cd. D


18. The diagram in Figure 13-1A that shows a meter properly connected for measuring voltage across the light bulb is:a. Ab. Bc. Cd. D


19. What voltage reading would you get if you connect both probes of a voltmeter to one end of a 1.5-volt battery?a. 1.5 voltsb. 1.5 ampsc. 0 voltsd. 4.5 volts


20. All of the following are considered conductors EXCEPT:a. iron.b. gold.c. silicon.d. copper.


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21. Materials through which current will not easily flow are called:a. conductors.b. semiconductors.c. insulators.d. absorbers.


22. Electric current will pass easily through a(n):a. absorber.b. conductor.c. semiconductor.d. insulator.


23. Which of the following could be a good conductor of electricity?a. Metal potb. Ceramic coffee cupc. Piece of foam packing materiald. Plastic spoon


24. If you look inside a stereo or telephone, you will find a circuit board, which has wires printed on it and is covered with little parts. Components called ____ are used to control current in the circuits on the board.a. resistorsb. wiresc. batteriesd. amperes


25. The ability of an object to resist current is called:a. potential difference.b. electrical inertia.c. alternating current.d. electrical resistance.


26. An ohm is the unit of measurement for:a. electrical power.b. voltage.c. current.d. resistance.


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27. The mathematical relationship between current, voltage, and resistance is known as ____ law.a. Kirchoff’sb. Faradayc. Ohm’sd. Murphy’s


28. The ratio of voltage to current represents a quantity that can be expressed using units of:a. volts.b. watts.c. amperes.d. ohms.


29. In the circuit below, 3 amps of current passes through the light bulb. The resistance of the light bulb is 3 ohms:

What is the voltage of the battery?

a. 1 voltb. 1 ohmc. 9 voltsd. 9 amps


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30. A battery connected to a light bulb with a resistance of 5 ohms causes a current of 2 amperes to flow through the bulb pictured in the diagram below:

The voltage across the light bulb is ____ volt(s).a. 0.4b. 1c. 2.5d. 10


31. As Jing toasts her morning waffle in the family toaster, 4.0 amps of current flows with a voltage of 120 volts across the toaster. The resistance of the toaster is:a. 30 watts.b. 30 ohms.c. 480 watts.d. 0.033 ohms.


32. A stereo receiver is plugged into a 120-volt outlet. If the receiver has a resistance of 240 ohms, how much current does it use?a. 2 ampsb. 2 voltsc. 0.5 ampsd. 60 volts


33. What happens to the current in a circuit with fixed voltage if you increase the resistance of the circuit?a. The current increases.b. The current decreases.c. The current stays the same.d. The voltage increases.


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34. This graph shows the current through a resistor as the voltage is changed:

The resistance of the bulb is ____ ohms.a. 6b. 0.67c. 5d. 1.5


35. A light bulb requires 2 amps to produce light. The resistance of the bulb is 3 ohms. How many batteries do you need if each battery is 1.5 volts?a. 6b. 4c. 1.5d. 5


36. A 120-volt household circuit has a circuit breaker that opens the circuit if it draws more than 12 amps of current. What is the minimum amount of resistance in the circuit required to keep the circuit breaker from activating?a. 0.1 ohmsb. 132 ohmsc. 1,440 ohmsd. 10 ohms


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Chapter 13: Electric Circuits—Multi-format Bank

MODIFIED TRUE/FALSE

1. In many circuit diagrams, any electrical device that uses energy is shown with a resistor symbol. _________________________


2. A closed circuit has a break in it. _________________________

ANS: F, open DIF: basic REF: section 13.1

3. Electric current is the difference in energy per unit of charge between two points in a circuit. _________________________

ANS: Fvoltagepotential differencevoltage drop


4. An ohm is the unit of measurement for current. _________________________

ANS: F, resistance DIF: basic REF: section 13.3

5. Electric current will flow easily through a conductor. _________________________


COMPLETION

1. A complete path through which electricity travels is called a ____________________.

ANS: circuit DIF: basic REF: section 13.1

2. A shorthand method of describing a real circuit using electrical symbols is called a _________________________ (two words).

ANS: circuit diagram DIF: basic REF: section 13.1

3. A device used to create an intentional break in a circuit to stop the flow of current is a ____________________.

ANS: switch DIF: basic REF: section 13.1

4. Differences in ____________________ cause charge to flow.

ANS: voltage DIF: basic REF: section 13.2

13-168

5. A battery uses ____________________ energy to move charges.

ANS: chemicalpotential


6. Devices that can be used to measure current in a circuit include the multimeter and the ____________________.

ANS: ammeter DIF: basic REF: section 13.2

7. Fuses protect a circuit from too much current by creating a break in the circuit but must be replaced. A device that may be reset while providing the same protection is a _________________________ (two words).

ANS: circuit breaker DIF: basic REF: section 13.2

8. Materials through which charge flows easily are called ____________________.

ANS: conductorssuperconductors


9. According to Ohm’s law, resistance is the ratio of ____________________ to ____________________.

ANS: voltage, current DIF: intermediate REF: section 13.3

10.

As shown in the graph above, plotting voltage on the x-axis and current on the y-axis, the slope of the resulting line represents the ____________________.

ANS: resistance DIF: advanced REF: section 13.3

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SHORT ANSWER

1. Why are circuit diagrams drawn?

ANS: Circuit diagrams are drawn using symbols to represent the arrangement of components in a circuit because it is easier and quicker than drawing realistic pictures of components.


2. To read the voltage, you accidentally connect the positive lead of a voltmeter to the negative terminal of a 1.5 volt battery and the negative lead to the positive terminal. What is the result?

ANS: The meter reads negative 1.5 volts or, if it is an analog meter, it may be “pinned” (go backwards against a stop).


3. You install two batteries in a flashlight so that their positive ends are facing each other. Will the flashlight work? Why or why not?

ANS: The flashlight will not work because the voltage, or potential difference, across the two batteries is zero. Instead of the batteries’ voltages adding together, the voltages subtract from each other.


4. Explain how a potentiometer is different from a fixed resistor.

ANS: A potentiometer can be adjusted to give a range of resistance; a fixed resistor has a resistance that cannot be changed.


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PROBLEM

1. Which of the circuits pictured below is an open circuit?

ANS: A


2. What should the voltmeter read (approximately)?

ANS: voltage of cell #1 + voltage of cell #2 = voltage of meter1.5 volts + 1.5 volts = 3.0 volts


3. A miniature light bulb with a resistance of 3 ohms is connected to a 6-volt source. How much current will flow through the bulb?

ANS: resistance = voltage ÷ current (or) R = V ÷ Icurrent = voltage ÷ resistance = 6 volts ÷ 3 ohms = 2 amps


4. If the current moving through the filament of a light bulb is 0.5 amps when the voltage across the bulb is 120 volts, what is the resistance of the bulb?

ANS:

R =VI

=120 volts0.5 amps

= 240 ohms = 240 Ω


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5. Typically, household appliances operate at 120 volts. What is the current flowing in the circuit of a microwave when the resistance of the microwave oven is 30 ohms?

ANS:

I =VR

=120 volts30 ohms

= 4 amps


A simple circuit is pictured in Figure 13-1. A light bulb is connected to a 9-volt battery that causes 3 amps of current through the bulb:

6. What is the resistance of the light bulb in the circuit shown in Figure 13-1?

ANS:

R =VI

=9 volts3 amps

= 3 ohms


7. If the light bulb in the circuit shown in Figure 13-1 is replaced with a light bulb having a resistance of 9 ohms, what would the new current in the circuit be?

ANS:

I =VR

=9 volts9 ohms

= 1 amp


8. If a second 9-volt battery is stacked with the battery shown in the circuit in Figure 13-1, what would the new current in the circuit be?

ANS:

I =VR

=9 volts + 9 volts

9 ohms= 2 amps


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9. This is a graph of the current that flows through a mini-bulb as the voltage is changed. Use the graph and your knowledge of Ohm’s Law to determine the resistance of the bulb.

ANS: resistance = voltage ÷ current (or) R = V ÷ Iresistance = (+4 volts - 0 volts) ÷ (+2 amps - 0 amps) = 2 ohms


10. A 120-volt household circuit has a fuse that breaks the circuit if more than 10 amps of current passes through it. What is the minimum amount of resistance in the circuit required to keep the fuse from blowing?

ANS:

R =VI

=120 volt10 amps

= 12 ohms


ESSAY

1. Describe a resistor and its function in a circuit.

ANS: A resistor is an electrical component that is designed to have a specific resistance over a wide range of currents. Resistors are used to control the amount of current in a circuit.


2. According to Ohm’s law, how is current related to the resistance in a circuit?

ANS: Ohm’s law states that V = I×R, therefore I = V÷R. Current is inversely proportional to resistance. As the resistance of a circuit increases, the current decreases. As the resistance of a circuit decreases, the current increases.


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OTHER

The circuit pictured contains a light bulb connected to a voltage source that causes 2 amps of current through the bulb.

Figure 13-2

1. Draw a circuit diagram to represent the circuit in Figure 13-2 using electrical symbols.

ANS:


2. Determine the resistance of the light bulb in Figure 13-2.

ANS:

R =VI

=1.5 volts + 1.5 volts

2 amps=

3 volts2 amps

= 1.5 ohms


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Chapter 14: Electrical Systems—Multiple Choice Bank

MULTIPLE CHOICE

1. If there is a break at any point in a series circuit, the current will:a. stop everywhere in the circuit.b. leak out of the break point.c. be decreased by one-half.d. continue through remaining unbroken circuit branches.


2. When more devices are added to a series circuit, the total circuit resistance:a. decreases.b. increases.c. stays the same.d. may increase or decrease, depending on the device.


3. Suppose you connect more and more light bulbs in series to a battery. What happens to the brightness of each bulb as you add more bulbs?a. The bulbs grow brighter with each new bulb added.b. The bulbs grow dimmer with each new bulb added.c. There is no change in brightness.d. The brightness may increase or decrease depending on the type of light bulb.


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The diagram below pictures three identical light bulbs, each with a resistance of 1 ohm, which are connected by resistance-free wires. A 9-volt battery supplies energy to the circuit.

Figure 14-1A

4. What type of circuit is the circuit in Figure 14-1A?a. Seriesb. Parallelc. Compoundd. Current


5. The total resistance for the circuit shown in Figure 14-1A is:a. 1 ohm.b. 1 volt.c. 3 ohms.d. 3 volts.


6. The current for the circuit shown in Figure 14-1A is:a. 3 amps.b. 3 ohms.c. 0.33 amps.d. 1 ohm.


7. The voltage drop across each light bulb in Figure 14-1A is ____ volt(s).a. 3b. 1c. 0.33d. 0


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8. The voltage drop across each resistor in the circuit below is ____ volts.

a. 1.5b. 3c. 2d. 9


9. The current in a series circuit:a. decreases to zero as it travels through the circuit.b. is the same at all points in a circuit.c. is greatest in the resistor with the highest resistance.d. is greatest in the resistor with the lowest resistance.


10. The current in each resistor in the circuit below is ____ ampere(s).

a. 1/3

b. 1c. 3d. 9


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11. Which of the following is TRUE about voltage in a series circuit?The total of all voltage drops must:a. equal the total current.b. add up to zero.c. add up to the total voltage supplied by the battery.d. never exceed the total circuit resistance.


12. A student connects six 3-ohm light bulbs in series to a 9-volt battery. The total circuit current is ____ ampere(s).a. 0.5b. 2c. 4.5d. 18


Study the circuit diagrams shown below (all bulbs are identical):

Figure 14-2A

13. Which of the circuit diagrams shown in Figure 14-2A is a series circuit?a. I onlyb. II onlyc. III onlyd. I and II only

ANS: C DIF: basic REF: section 14.1, section 14.2

14. Which of the circuit diagrams shown in Figure 14-2A is a parallel circuit?a. I onlyb. II onlyc. III onlyd. I and II only

ANS: D DIF: basic REF: section 14.1, section 14.2

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15. When a new branch containing a resistor is added to a parallel circuit, the total circuit resistance:a. decreases.b. increases.c. stays the same.d. may increase or decrease, depending on the device.


16. What is the basic difference between series and parallel circuits?a. Simple series circuits are not used in electrical devices; parallel circuits are used in all

electrical devices.b. In a series circuit, there are multiple paths for the flow of charge; in a parallel circuit,

there are only two paths.c. A series circuit contains one path for the flow of charge; a parallel circuit contains more

than one path.d. A series circuit obeys Ohm’s law; a parallel circuit does not obey Ohm’s law.


17. The wiring in your home uses ____ circuits.a. parallelb. seriesc. two-wayd. three-way


18. Which of the following statements best describes the difference between series and parallel circuits?a. Series circuits are battery circuits, and parallel circuits are generator circuits.b. Series circuits have a single path, and parallel circuits have two or more paths.c. Series circuits are used in computers, and parallel circuits are used in homes.d. Series circuits have one switch in them, and parallel circuits have two switches in them.

ANS: B DIF: intermediate REF: section 14.1, section 14.2

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19. The voltage drop across each resistor in the circuit below is ____ volt(s).

a. 0.2b. 5c. 6d. 12


20. The current in each resistor in the circuit is ____ ampere(s).

a. 1/3

b. 1c. 3d. 9


21. A lamp has a short circuit. Which of the following statements best describes the lamp’s circuit?a. The circuit is drawing a large amount of current.b. The circuit has a path of very low resistance.c. The lamp will not turn on.d. All of the above


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22. The voltage across the 1-ohm resistor pictured below is ____ volt(s).

a. 1/3

b. 2/3

c. 1d. 3


23. Kirchoff's current law applies to a parallel circuit because it states that:a. current is the same everywhere throughout one entire circuit.b. current is the same everywhere throughout branching circuit paths.c. current stays the same as more branches are added to a parallel circuit.d. all the current flowing into a branch point must flow out again.


24. A student connects three 1-ohm light bulbs to a 9-volt battery in parallel. The total circuit current is ____ ampere(s).a. 1b. 3c. 9d. 27


25. Which of the following would create a total resistance of 0.5 ohm?a. Four 2-ohm resistors connected in parallelb. Four 2-ohm resistors connected in seriesc. Eight 2-ohm resistors connected in paralleld. Two 2-ohm resistors connected in series


26. A circuit containing two identical branches has:a. one-half the resistance it would have if it only contained one of the branches.b. twice the resistance it would have if it only contained one of the branches.c. the same resistance it would have if it only contained one of the branches.d. no resistance at all.


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In the circuit shown below, three identical flashlight bulbs are screwed into sockets and are lighted when the circuit is closed:

Figure 14-3A

27. Which bulb draws the least amount of current in Figure 14-3A?a. Bulb Ab. Bulb Bc. Bulb Cd. Bulbs B and C draw an equal amount of current but draw less than bulb A.


28. If you unscrewed bulb A in Figure 14-3A:a. only bulb B would go out.b. only bulb C would go out.c. bulbs B and C would go out.d. bulbs B and C would remain lit.


29. If you unscrewed bulb C in Figure 14-3A:a. only bulb A would go out.b. only bulb B would go out.c. bulbs B and C would go out.d. bulbs B and A would remain lit.


30. A 75-watt light bulb uses 75:a. joules of energy until it burns out.b. joules of energy every second.c. joules of energy every hour.d. 75 watts of power every hour.


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31. The power used by a circuit can be found by:a. using Ohm’s law.b. dividing voltage by current.c. adding all resistances.d. multiplying voltage and current.


32. What do we buy from the electric utility company?a. Power, in wattsb. Energy, in kilowatt-hoursc. Current, in amperesd. Voltage, in volts


33. Which of the following is TRUE about alternating current?a. Alternating current flows in one direction only.b. Batteries run on alternating current.c. The electricity in your house uses alternating current.d. Alternating current is easy to recharge.


34. The watt is a unit that represents the:a. amount of energy consumed by electrical appliances.b. flow of charge in a circuit.c. rate at which energy is changed from one form to another.d. potential energy difference between two places in a circuit.


35. How much would it cost to operate a 100-watt light bulb for 10 hours if the cost of electric energy is 10 cents per kilowatt-hour?a. 1 dollarb. 10 dollarsc. 10 centsd. 1 cent


36. How much does it cost to operate a 1,500-watt space heater for 8 hours if the cost of electric energy is 12 cents per kilowatt-hour?a. $1.44b. $9.60c. $1.50d. $0.18


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37. Which of the following devices draws the most current when operating on a 120-volt circuit?a. 10-watt clock radiob. 40-watt light bulbc. 50-watt fand. Each item above draws the same current.


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Chapter 14: Electrical Systems and Power—Multi-format Bank

MODIFIED TRUE/FALSE

1. A series circuit contains branching points and multiple paths for current to flow through. _________________________

ANS: F, parallel circuit DIF: basic REF: section 14.2

2. Each branch of a parallel circuit has the same voltage. _________________________


3. Kirchhoff’s current law states that all the current entering a branch point must exit the point. _________________________


4. A kilowatt-hour (kWh) is a unit of power. _________________________

ANS: F, energy DIF: intermediate REF: section 14.3

5. The current from a battery is always direct current (DC). _________________________

ANS: T DIF: intermediate REF: section 14.3

COMPLETION

1. Each separate resistor in a series circuit creates a(n) ____________________ drop.

ANS: voltage DIF: basic REF: section 14.1

2. The total circuit resistance ____________________ as more resistors are added in parallel.

ANS: decreases DIF: basic REF: section 14.2

3. An appliance’s energy use over time is called its ____________________ (two words).

ANS: power rating DIF: basic REF: section 14.3

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SHORT ANSWER

1. The circuit shown below has 3 identical bulbs connected in series to a battery. If 1 bulb is unscrewed, what will happen to the 2 remaining bulbs?

ANS: The other two bulbs will go out when one bulb is unscrewed.


2. Give an example of a circuit that uses alternating current and an example of a circuit that uses direct current.

ANS: Answers may vary. Correct answers include:Alternating current: household circuitsDirect current: battery circuits


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PROBLEM

1. A series circuit contains a 9 volt battery and three resistors of 1 ohm, 3 ohms, and 5 ohms. What is the current in the circuit?

ANS: total resistance = 1Ω + 3Ω + 5Ω = 9 Ω

current = voltage ÷ resistance

current = 9 V ÷ 9Ω = 1 amp


A 0.5-ohm bulb and a 2-ohm bulb are connected in parallel to a 3-volt battery.

2. Draw the circuit diagram, and label the values for voltage and resistance.

ANS:


3. What is the voltage across each bulb?

ANS: A parallel circuit has constant voltage in each branch, therefore the voltage across each bulb is 3 volts.


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4. What is the current through the branch with the 2-ohm bulb? Show your work.

ANS:

current =voltage

resistance,or I =

VR

3 volts2 ohms

= 1.5 amps


5. What is the current through the branch with the 0.5-ohm bulb? Show your work.

ANS:

I =VR

3 volts0.5 ohm

= 6 amps


6. What is the total circuit current (ignore the resistance of the wires and batteries)?

ANS: 1.5 amperes + 6 amperes = 7.5 amps


7. A 2,000-watt electric stove is used to simmer a pot of stew. If it takes 3 hours to simmer a stew, how much would it cost to do this task if the electrical energy cost is 10 cents per kilowatt-hour?

ANS:

2000 watts ×1 kilowatt1000 watts

= 2 kilowatts

energy = power × timeenergy = 2 kW × 3 hrsenergy = 6 kWhcost = energy × ratecost = 6 kWh × $0.10/kWhcost = $0.60


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8. How much current is used by a 1,200-watt hairdryer operating on a 120-volt circuit?

ANS: power = current × voltage, or P = I × Vcurrent = power ÷ voltagecurrent = 1,200 watts ÷ 120 voltscurrent = 10 amps


9. Measured in kilowatt-hours, how much energy does a 4,500-watt water heater element use in 2 hours?

ANS: energy = power × time

kilowatt-hours = watts ×1 kilowatt

1,000 watts× hours

energy = 4,500 wattsÊËÁÁ

ˆ¯ ×

1 kilowatt1,000 watts

Ê

Ë

ÁÁÁÁÁÁÁ

ˆ

¯

˜˜˜

× 2 hours

energy = 9 kWh


A radio’s label identifies its power rating as 12 watts. Assume that the radio is plugged into a 12-volt outlet as you answer the following questions:

10. How much current is used by this radio?

ANS: power = current × voltage (or) P = I × Vcurrent = power ÷ voltagecurrent = 12 watts ÷ 120 voltscurrent = 0.1 amps


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11. The power company charges 10 cents per kilowatt-hour of energy. How much would it cost to run this radio for 100 hours?

ANS:

12 watts ×1 kilowatt1000 watts

= 0.012 kilowatts

energy = power × timeenergy = 0.012 kW × 100 hrsenergy = 1.2 kWhcost = energy × ratecost = 1.2 kWh × $0.10/kWhcost = $0.12


12. If a 60-watt bulb is connected to a 120-volt source, what is the resistance of the bulb?

ANS: power = current × voltage (or) P = I × Vcurrent = power ÷ voltagecurrent = 60 watts ÷ 120 voltscurrent = 0.5 amps

voltage = current × resistanceresistance = voltage ÷ currentresistance = 120 volts ÷ 0.5 ampsresistance = 240 ohms


OTHER

If the statement about a circuit is true for a series circuit, place an “S” in the blank. If the statement is true for a parallel circuit, place a “P” in the blank.

1. ____ There are multiple paths for current.

ANS: P


2. ____ There is only one path for current.

ANS: S


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3. ____ Current is the same at every point in the circuit.

ANS: S


4. ____ Total battery voltage is equal to the sum of the voltages across each resistor.

ANS: S


5. ____ The voltage across each branch is the same and is equal to the battery voltage.

ANS: P


The circuit pictured contains 3 identical light bulbs. They are connected to a voltage source which causes 2 amperes of current to flow through each of the bulbs.

Figure 14-1

6. Identify the type of circuit in Figure 14-1.

ANS: It is a parallel circuit.


7. Determine the current produced by the source in Figure 14-1.

ANS: currenttotal = current1 + current2 + current3

currenttotal = 6 amps


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8. What is the resistance of each bulb in the circuit shown in Figure 14-1?

ANS: Each bulb is identical and the current for each bulb is 2 ampsThe voltage for the circuit is 3 volts

resistance = voltage ÷ currentresistance = (3 volts) ÷ (2 amps)resistance = 1.5 ohms


9. What is the total resistance of the circuit shown in Figure 14-1?

ANS:

Resistance1 + 2 =R1 × R2

R1 + R2

=1.5 ohms × 1.5 ohms1.5 ohms + 1.5 ohms

= 0.75 ohm

Resistance1 + 2 + 3 =R1 + 2 × R3

R1 + 2 + R3

=0.75 ohm × 1.5 ohm0.75 ohm + 1.5 ohm

= 0.5 ohm


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Chapter 15: Electrical Charges and Forces—Multiple Choice Bank

MULTIPLE CHOICE

1. A device use to observe electric forces is a(n):a. galvanometer.b. voltmeter.c. compass.d. electroscope.


2. The unit of charge is the:a. ohm.b. ampere.c. volt.d. coulomb.


3. The negatively charged particle in an atom is a(n):a. electron.b. proton.c. neutron.d. neutrino.


4. An object with equal amounts of positive and negative charge is called:a. positively charged.b. negatively charged.c. neutral.d. electrically charged.


5. Positive electric charges:a. attract both positive charges and negative charges.b. repel both positive charges and negative charges.c. attract positive charges and repel negative charges.d. repel positive charges and attract negative charges.


6. Electric charge is:a. caused by two fluids, as described by Benjamin Franklin.b. present in metals only.c. a fundamental property of matter that has two types, positive and negative.d. found only in non-living material.


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7. The buildup of static charge on an object is called ____ electricity.a. inductiveb. staticc. contactd. charged


8. One ampere, or amp, is defined as ____ per second.a. a difference of one voltb. the flow of one coulombc. the resistance of one ohmd. the capacity of one farad


9. The charge of a proton and the charge of an electron have:a. different amount of charge and opposite sign.b. the same amount of charge and opposite sign.c. different amount of charge and the same sign.d. the same amount of charge and the same sign.


10.

The diagram that best represents the charge distribution on a neutral electroscope when a negatively charged rod is held near it is:a. A.b. B.c. C.d. D.


11. A rod and a piece of cloth are rubbed together. If the rod acquires a charge of +1 × 10-6 coulomb, the cloth acquires a charge of:a. 0.b. +1 × 10-6 coulomb.c. -1 × 10-6

coulomb.d. +1 × 10+6

coulombs.


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12. An electrically neutral object can be attracted by a positively charged object because:a. like charges repel each other.b. the charges on a neutral object can be redistributed.c. the neutral object becomes charged by friction.d. the net charge in a system varies.


13.

Determine the electric force exerted on sphere A.a. 9 × 109 newtonsb. 1.3 × 1011 newtonsc. 1.4 × 1010 newtonsd. 1.6 × 109

newtons


14. As the distance between two positively charged objects increases, the force between them:a. increases.b. decreases.c. cannot be determined.d. remains the same.


15. The electric force between a 5-coulomb charge and a 1-coulomb charge 9,000 meters apart is:a. 5,000,000 newtons.b. 666 newtons.c. 556 newtons.d. 0.000556 newtons.


16. If the distance between two charges is reduced by half, the electric force between them:a. decreases by 1/2.b. decreases by 1/4.c. increases by 2 times.d. increases by 4 times.


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17. Two point charges attract each other with a force of 8.0 × 10-5 newtons. If the distance between the charges is doubled, the force of attraction will become ____ newtons.a. 16 × 10-5

b. 2.0 × 10-5

c. 64 × 10-5

d. 4.0 × 10-5


18. Suppose you rub an inflated party balloon on a carpet, hold the balloon next to a wall, and discover that it “sticks” to the wall. Why did the balloon stick to the wall?a. The total charge on the balloon and wall becomes zero, so attraction between the two can

occur.b. Like charges on the balloon and wall cause an attraction between the two.c. Balloons contain a special “atomic glue” that allows them to cling to other objects.d. Excess charge builds up on the balloon and electrostatic forces allow the balloon and wall

to be attracted to one another.


19. An electric current in a metal consists of moving:a. nuclei.b. protons.c. neutrons.d. electrons.


20. Because of Ben Franklin’s work, the direction of current in an electrical circuit is defined as going from:a. positive to negative.b. negative to positive.c. positive to positive.d. negative to negative.


21. Almost all of the electrons flowing through a battery circuit come from atoms:a. in the wire conductor.b. in the circuit components.c. involved in chemical reactions at the battery's negative terminal.d. involved in chemical reactions at the battery's positive terminal.


22. The electrons in an insulator are best described as:a. free to move.b. fixed in place.c. flowing charges.d. a potential difference.


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23. The electric field around two positive charges looks most like:

a. c.

b. d.


24. A capacitor can be charged by:a. a resistor.b. a battery.c. wires.d. an ammeter.


25. Capacitance is measured in units of:a. farads.b. volts.c. ohms.d. joules.


26. A capacitor is a device that:a. charges electrons.b. charges protons.c. stores electrical energy.d. stores chemical energy.


27. When a capacitor is discharged:a. it creates a current until all its stored energy has been converted.b. the current it creates decreases over time.c. electrons move from the negative plate to the positive plate until both plates are neutral.d. All of the above


28. Capacitance is the:a. ability of a capacitor to store charge.b. ability of a capacitor to store resistance.c. buildup of electric charge on an object.d. flow of electric charge.


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29. All of the following will increase the capacitance of a parallel plate capacitor EXCEPT:a. increasing the size of the capacitor’s plates.b. increasing the voltage of the battery that charges it.c. using a material that provides better insulation between the plates.d. decreasing the distance between the plates.


15-198

Chapter 15: Electrical Charges and Forces—Multi-format Bank

MODIFIED TRUE/FALSE

1. The coulomb is the unit of measure for charge. _________________________


2. The electric force between two charged objects increases as the distance between them increases. _________________________

ANS: F, decreases DIF: intermediate REF: section 15.1

3. Because of Ben Franklin’s work, current is always defined as going from negative to positive. _________________________

ANS: F, positive to negative DIF: basic REF: section 15.2

4. Some of the electrons in insulators are free to move throughout the material. _________________________

ANS: F, conductors DIF: basic REF: section 15.2

5. An electroscope is a device that can be used to observe electric forces. ________________________


6. A capacitor is a device that stores electrical energy. _________________________


7. Capacitance is measured in ohms. _________________________

ANS: Ffaradsmicrofarads


COMPLETION

1. The build up of electric charge on an object is called ____________________ electricity.

ANS: static DIF: basic REF: section 15.1

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2. If an object has more negative charges than positive charges, the ____________________ charge is negative.

ANS: netexcess


3. Atoms are ____________________ when one end is positive and one end is negative.

ANS: polarized DIF: basic REF: section 15.1

4. Two negative charges will ____________________ each other.

ANS: attract DIF: basic REF: section 15.1

5. An object with equal amounts of positive and negative charge is called ____________________.

ANS: neutral DIF: basic REF: section 15.1

6. One ampere is the flow of one ____________________ per second.

ANS: coulomb DIF: intermediate REF: section 15.2

7. When we say current is moving through a circuit, we mean ____________________ (two words) is moving through the circuit.

ANS: electric charge DIF: intermediate REF: section 15.2

8. ____________________ is the measure of a capacitor’s ability to store charge.

ANS: Capacitance DIF: basic REF: section 15.3

SHORT ANSWER

1. Name the two ways that an electrically neutral object can become positively charged.

ANS: An electrically neutral object can either lose negative charge or gain positive charge to become positively charged.


2. Two positively charged objects are separated from each other by 1 centimeter. What is the direction of the electrical force between them?

ANS: The electrical force between them is a repulsive force, pushing the charges away from each other.


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3. Name the two factors that determine the strength of the electrical force between two charged objects, and describe how these two factors influence the force between the two objects.

ANS:

The two factors are the amount of excess charge on the objects and the distance between them. The force is stronger when the amount of charge is greater and when they are closer together.


4. If the distance between charges is reduced by half, what happens to the force between them?

ANS: The force between charges is inversely proportional to the square of the distance between them. Halving the distance increases the force by 4 times.


5. What does the term “charging by friction” mean, and what happens to the charge of the objects involved? Give one example.

ANS: Charging by friction occurs when two neutral objects are rubbed together, and charge is transferred from one to the other. One object loses negative charge. Objects charged in this manner have opposite charges and attract each other.

Examples may vary. Correct examples include:clothes from a dryer, certain semi-precious stones rubbed with fabric, a glass rod rubbed with silk, a person dragging your feet over a floor or carpet


6. Explain what creates a current in a conductor.

ANS: Some of the electrons in conductors are not fixed to individual atoms but are free to move throughout the material. Moving electrons create current.


7. Describe the speed at which the free electrons in an electrical current move.

ANS: They move very slowly at drift velocity.


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8. How is a capacitor charged? What does it mean for a capacitor to be charged?

ANS: A capacitor is charged by connecting it to a battery or other source of voltage. A capacitor is charged when one of its plates has a positive net charge and one of its plates has a negative net charge; however, the net charge on the capacitor as a whole is zero.


9. List two devices that use capacitors.

ANS: Almost all electrical appliances use capacitors. Correct answers include:televisioncamera flashcomputerdefibrillator


PROBLEM

1.

What is the charge on the object pictured?

ANS: The charge on the object is -5.positive charge + negative charge = net (or excess) charge+10 + (-15) = -5


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2. Two 3-coulomb charged metal spheres are separated by 900 meters. What is the electric force between the metal spheres?

ANS:

FE = kq 1 q 2

r2 = 9 × 109 N ⋅m2 /C2ÊËÁÁÁ

ˆ¯˜ 3 C( ) 3 C( )

900 m( ) 2 = 1 × 105 N = 100,000 newtons


3. Calculate the electric force between a proton and an electron. A proton has a charge of 1.6 × 10-19 coulombs; an electron has a charge of -1.6 × 10-19 coulombs; and they are separated by 3 × 10-11 meters.

ANS:

FE = kq 1 q 2

r2 = 9 × 109 N ⋅m2/C2ÊËÁÁÁ

ˆ¯˜

1.6 × 10−19 CÊËÁÁÁ

ˆ¯˜ −1.6 × 10−19 CÊËÁÁÁ

ˆ¯˜

3 × 10−11 mÊËÁÁÁ

ˆ¯˜

2 = 2.6 × 10−7 newtons


4. Two objects of equal charge are repelled by an electrical force of 200 newtons. If the distance separating the objects is 1 meter, what are the charges of the objects?

ANS:

FE = kq 1q 2

r2

FE = 9 × 109 N ⋅m2 /C2ÊËÁÁÁ

ˆ¯˜

q 1 q 2

1 m( ) 2

200 N = 9 × 109 N ⋅m2/C2ÊËÁÁÁ

ˆ¯˜

q 1q 2

1 m( ) 2

2.2 × 109 = q 1 q 2

q 1 = q 2 = 1.5× 10−4 coulombs


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ESSAY

1. What are two similarities between gravitational force and electric force?

ANS: Any two of the following three answers are correct:

1) Both gravitational force and electric force are due to a fundamental property of matter. For gravitational force, the property is mass, and for electric force, the property is charge.

2) More charge results in stronger electric force; more mass results in stronger gravitational force.

3) Both forces decrease as distance increases, following an inverse square law.


2. Describe the three processes that are used to charge objects.

ANS: 1) Charge by induction: No contact is made between the charged object and the object being charged. Placing the charged object close by forces electrons to move in the object being charged. Grounding the object being charged causes electrons to move into or out of it and allows it to have a net charge. The original object’s net charge does not change.

2) Charge by friction: By rubbing two objects together, electrons are transferred between the two objects. One object gains electrons and has a negative net charge. One object loses electrons and has a positive net charge.

3) Charge by contact: Contact is made between a charged object and a neutral object. Electrons are transferred between the two objects and the neutral object becomes charged.


3. Describe what happens when a capacitor is discharged.

ANS: Electrons are quickly removed from the negative plate and added to the positive plate until both plates are neutral, allowing current to flow until the capacitor is completely discharged.


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OTHER

1. Draw the electric force field lines between two charged objects, one positive and one negative.

ANS:


16-205

Chapter 16: Magnetism—Multiple Choice Bank

MULTIPLE CHOICE

1. Placing the north pole of a magnet near the south pole of another magnet results in:a. an attractive force between the magnets.b. a repulsive force between the magnets.c. an electric force between the magnets.d. no force between the magnets.


2. A student places two magnets with their north poles facing each other about 70.0 centimeters apart. When she moves one magnet toward the other, the first magnet repels the second at a distance of 26 centimeters. She repeats the procedure, but now places the magnets so the south pole of one faces the north pole of the other.

She is likely to observe that the first magnet will:a. again repel the second at a distance of 26 centimeters.b. attract the second at a distance of 26 centimeters.c. repel the second at a distance of 52 centimeters.d. attract the second at a distance of 52 centimeters.


3. If a 12-inch long bar magnet is cut into two pieces, one inch from the north pole end of the magnet:a. the short piece of the magnet has a north pole on one end and no pole on the other.b. the long piece of the magnet has a south pole on both ends.c. the short piece has a north pole on both ends.d. both pieces have a north and a south pole on each end.


16-206

Figure 16-1A

4. Which pair of objects in Figure 16-1A experiences a repulsive force?a. A and Bb. A and Cc. B and Dd. B and C


5. Which pair of objects in Figure 16-1A experiences an attractive force?a. A and Bb. A and Cc. B and Dd. B and C


A magnet is shown surrounded by its magnetic field.

Figure 16-2A

6. In which area of Figure 16-2A is the magnetic field strongest?a. Ab. Bc. Cd. D


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7. In Figure 16-2A, which direction should the magnetic field lines be pointing?a. From South to Northb. From North to Southc. From East to Westd. From West to East


8. The magnetic field strength inside a current-carrying coil will be larger if the coil is wound around a:a. vacuum.b. wooden rod.c. glass rod.d. iron rod.


9. The source of a material’s magnetism is the:a. charge of its protons.b. mass of its neutrons.c. spin of its electrons.d. density of its nucleus.


10. Materials in which the magnetic fields of individual electrons in an atom cancel out so that each atom has zero net magnetic field are known as:a. ferromagnetic.b. paramagnetic.c. diamagnetic.d. monomagnetic.


11. Materials in which each atom has a tiny magnetic field, but the north and south poles of atoms within the material are randomly arranged so that the magnetic fields cancel out, are known as:a. nonmagnetic.b. paramagneticc. diamagnetic.d. monomagnetic.


12. If you reverse the direction of current flow in an electromagnet:a. the north and south poles are reversed.b. the magnet is neutralized.c. the strength of the magnetic field increases.d. a short circuit occurs.


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The diagram represents an iron nail wrapped with a current carrying wire.

Figure 16-3A

13. What type of device does Figure 16-3A represent?a. Permanent magnetb. Electromagnetc. Compassd. Potentiometer


14. Using the right hand rule, the magnetic poles of the device in Figure 16-3A are located:a. North at the “head” and South at the “point.”b. North at the “point” and South at the “head.”c. East at the “point” and West at the “head.”d. East at the “head” and West at the “point.”


15. Dani and Gina are trying to make a permanent magnet out of an iron bar. Any of the following methods would permanently magnetize the iron bar EXCEPT:a. stroking the iron bar with a powerful magnet.b. placing the iron bar in a very strong magnetic field.c. placing the iron bar near a very strong electromagnet.d. placing the iron bar near a diamagnetic material.


16. An example of a ferromagnetic material is a:a. ceramic mug.b. nail attracted to a bar magnet.c. penny.d. CD.


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17. Which of the following creates a magnetic field?a. A metal ball with 2 coulombs of static charge on itb. A piece of aluminumc. A coil of wire carrying currentd. A diamagnetic material


18. A permanent magnet can be demagnetized by:a. dropping it on a hard surface.b. heating it to very high temperature.c. forcing two north poles together.d. All of the above


19. Three ways you can increase the strength of an electromagnet are ____, ____ and add iron to the core.a. decrease the number of coils, increase the currentb. increase the number of coils, increase the currentc. increase the number of coils, decrease the currentd. decrease the number of coils, decrease the current


20. Electromagnets are generally more useful than permanent magnets for all of the following reasons EXCEPT:a. they are always magnetized.b. their polarity can be changed.c. their strength can be altered.d. the magnetism can be turned off.


21. All atoms act like tiny magnets. Why do only a few materials show magnetic properties?a. Magnetic materials have atoms that are much stronger magnets than the atoms of other

materials.b. Atomic magnets are magnified when combined with a rare substance. Magnetic materials

contain this rare substance.c. We see magnetic properties only if atomic magnets line up with Earth’s geographic south

and north poles. In magnetic materials, this arrangement can occur.d. We see magnetic properties only if atomic magnets line up in the same direction

throughout a material. In magnetic materials, this arrangement can occur.


22. If a pin is brought close to a magnet, it is attracted to the magnet and attracts other pins to it. If the pin is removed from the magnet, it does not attract other pins.The pin might be referred to as:a. a hard magnet.b. a soft magnet.c. magnetic mono-pole.d. diamagnetic material.


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23. Earth’s magnetic north pole is:a. aligned with the north star.b. aligned with Earth's geographic north pole.c. under Antarctica, near Earth's geographic south pole.d. at the equator.


24. The earliest records of magnetically aided navigation are found in the history of the:a. Japanese.b. Italians.c. Greeks.d. Chinese.


25. The difference between true geographic north and the “north” indicated by a compass is a difference measured in degrees and known as:a. inclination.b. declination.c. azimuth.d. elevation.


26. According to historical data and current scientific theory, the statement that is NOT true concerning Earth’s magnetic field is that the field:a. reverses every 500,000 years.b. is weakening by 7% every 100 years.c. will reverse within the next 2,000 years.d. will completely disappear in the future.


27. The unit used to measure the strength of a magnetic field is the:a. ohm.b. gauss.c. ampere.d. coulomb.


28. Earth behaves like a giant:a. electric circuit.b. permanent magnet.c. compass.d. electromagnet.


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29. Which compass in the diagram below is pointing in the wrong direction?

a. Ab. Bc. Cd. D


30. Magnetic declination can best be described as the:a. difference between the magnetic field and Earth’s surface.b. magnetic field strength of Earth at the equator.c. tendency for the magnetic field of Earth to reverse itself.d. difference between directions to true north and magnetic north.


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Chapter 16: Magnetism—Multi-format Bank

MODIFIED TRUE/FALSE

1. The unit used to measure the strength of a magnetic field is the ohm. _________________________

ANS: F, gauss DIF: basic REF: section 16.3

COMPLETION

1. A model of the forces exerted by a magnet is called a magnetic ____________________.

ANS: field DIF: basic REF: section 16.1

2. If two opposite poles of magnets are facing each other, the magnets will ____________________ one another.

ANS: attract DIF: basic REF: section 16.1

3. In ____________________ magnets, the magnetic fields of individual atoms are aligned in a similar direction.

ANS: permanent DIF: basic REF: section 16.2

4. A material in which the magnetic fields of individual electrons in each atom cancel so that each atom has zero net magnetic field is known as ____________________.

ANS: diamagnetic DIF: basic REF: section 16.2

5. Atoms aligned in such a way that their magnetic fields do not all cancel one another are found in ____________________ materials.

ANS: ferromagnetic DIF: intermediate REF: section 16.2

6. The needle of a compass will always point north because the core of the earth acts like a large ____________________ roughly aligned in the north-south direction.

ANS: magnet DIF: basic REF: section 16.3

7. Earth’s core is surrounded by a magnetic field aligned so that its magnetic south pole is located near its geographic ____________________ pole.

ANS: north DIF: intermediate REF: section 16.3

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SHORT ANSWER

1. Is it possible to have a magnet with only a north pole? Explain.

ANS: No. All magnets have two opposite poles, north and south. It is impossible to have only a north or south pole by itself.


2. The forces between two magnets depend upon the magnets’ alignment. Explain how you might cause attractive and repulsive forces between two magnets.

ANS: Attractive forces exist between two magnets when unlike poles face each other. Repulsive forces exist when like poles are facing one another.


3. What two pieces of information can you get from a magnetic field diagram?

ANS: The direction and the relative strength of the magnetic field


4. A strong magnet and a weak magnet are placed north pole to south pole and are attracted to each other with a magnetic force. Which magnet has the stronger force?

ANS: According to Newton’s third law, they exert the same force on each other.


5. Name 3 ferromagnetic materials.

ANS: Answers may vary. Correct answers include:The most common types of ferromagnetic material are iron, cobalt, and nickel.


6. Name 2 methods that might be used to demagnetize a material.

ANS: Any two of these four answers are correct:Heating, dropping, hitting, or vibrating the magnet can demagnetize it.


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7. What term describes a material that is very weakly magnetized due to its randomly arranged magnetic domains?

ANS: Paramagnetic


8. Describe how to make an electromagnet.

ANS: Electromagnets are magnets created when there is electric current flowing in a wire. The simplest electromagnet uses a coil of wire that must be wrapped around a piece of metal. Iron is often used. Because iron is magnetic, it concentrates the magnetic field created by the current in the coil.


9. Name two ways to increase the strength of an electromagnet.

ANS: Any two of these three answers are correct:1) Increase current flow in the wire.2) Increase the amount and type of material in the core.3) Increase the number of turns of wire in the coil.


10. Several compasses are placed around a bar magnet. Which end of the magnet is its north pole?

ANS: B


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11. In this diagram of Earth’s magnetic field, where is the magnetic field the strongest?

ANS: At point B. The field is strongest at the north or south magnetic poles, not at the north or south geographic poles.


ESSAY

1. Explain why a magnet always attracts ferromagnetic materials even when they are not magnets.

ANS: If the north pole of a magnet is held near an object like a thumbtack, atoms in the tack will adjust their orientation so their south poles point toward a magnet’s north pole. The thumbtack will stick to the magnet. If the south pole of the magnet is held near the thumbtack, the opposite happens. In either case, the thumbtack is attracted to the magnet.


2. How can a permanent magnet be created?

ANS: By placing it in an extremely strong magnetic field or stroking it many times with a magnet


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3. If a permanent magnet is used to pick up one pin, that pin will, in turn, attract a second pin that will attract a third pin and so on. Explain how the magnetism shown by the pins and the permanent magnet differ.

ANS: The permanent magnet (referred to as a hard magnet) is made from a material that is difficult to initially magnetize. However, it does not easily lose its magnetism. The pins are easily magnetized while in contact with another magnet but lose their magnetism as soon as the permanent magnet is removed. They are referred to as soft magnets.


4. Describe the mechanism that provides the magnetic field that surrounds Earth.

ANS: Earth’s core contains dense, molten, metallic material that slowly circulates. The motion of the molten material creates electric currents that produce a magnetic field like that made by any other electromagnet. Earth is, therefore, an electromagnet, not a permanent magnet.


5. Name an example of a naturally-occurring magnetic material, and describe how it its magnetic properties have been used.

ANS: Either one of the following two answers are correct.

1) Lodestone is a naturally-occurring magnetic mineral. Lodestone has been used by humans since as early as 500 B.C. for navigation purposes. Lodestone was used in the earliest compasses by the Chinese as early as 220 B.C.

2) The mineral magnetite occurs naturally in animals and bacteria. Tiny crystals of magnetite act like compasses and allow the animals to sense Earth’s magnetic field.


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OTHER

The diagram represents an iron nail wrapped with a current carrying wire.

Figure 16-1

1. What type of device does Figure 16-1 represent?

ANS: It represents an electromagnet.


2. Label the pointed end and the head of the nail in Figure 16-1 with an “N” and “S” to represent the magnetic north and south poles of the nail.

ANS: N at the “head” and S at the “point”


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3. If the current flows through the wire as pictured in Figure 16-1, draw lines of force as they might surround the nail.

ANS: The lines will surround the nail, emanating from the head (N) on one end and entering the pointed end (S)at the other. The student’s diagram should indicate both orientation of lines and direction of field for full credit.


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Chapter 17: Electromagnets and Induction—Multiple Choice Bank

MULTIPLE CHOICE

1. When current flows through a coil of wire, you have a(n):a. superconductor.b. electromagnet.c. ceramic magnet.d. semiconductor.


2. Hans Christian Oersted discovered that magnetism was related to electricity when he placed a compass needle in the presence of a current carrying wire and the:a. current immediately turned off.b. current reversed direction.c. compass needle moved as if the wire were a magnet.d. compass needle always pointed north.


3. The magnetic field is strongest for a straight wire carrying electric current:a. far from the wire.b. close to the wire.c. at one end of the wire.d. There is no magnetic field around the wire.


4. The magnetic field is strongest for a wire carrying electric current that has been looped into a coil:a. inside the coil.b. outside the coil.c. far away from the coil.d. There is no magnetic field around the wire.


5. A simple electromagnetic device consisting of a coil with many turns is known as a:a. solenoid.b. electric motor.c. semiconductor.d. commutator.


6. An electric charge creates magnetism by:a. static.b. isolation.c. moving.d. domain.


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7. If you increase the current in an electromagnet:a. the north and south poles will be switched.b. the magnetic field will be stronger.c. the magnetic field will disappear.d. a short circuit will be created.


8. Solenoids and other coil electromagnets are used in all the following devices EXCEPT:a. speakers.b. electric motors.c. doorbells.d. batteries.


9. Two parallel current-carrying wires next to each other on a table are shown in the diagram:

If their currents are in opposite direction:a. the wires will lift off the table.b. the wires will move away from each other.c. the wires will move toward each other.d. nothing will happen.


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10. An electric current moving upward through a straight wire creates a magnetic field. The diagram that correctly represents this magnetic field is:

a. A.b. B.c. C.d. D.


11. The purpose of a commutator in an electric motor is to:a. spin around so the motor can do useful work.b. create a voltage drop so that current flows.c. switch the electromagnets from north to south and back again.d. attract and repel the magnets in the rotor.


12. The device that switches the polarity of the electromagnets giving motion to the rotor in an electric motor is the:a. armature.b. commutator.c. brush.d. knife switch.


13. The rotating element of a motor is often referred to as the:a. field coil.b. brush.c. commutator.d. armature.


14. The main parts of a motor include all of the following EXCEPT a :a. rotating element with magnets.b. double-throw knife switch.c. stationary magnet surrounding the rotor.d. commutator.


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15. An electric motor spins because:a. the voltage pushes the motor around.b. an electromagnet attracts and then repels magnets in the rotor.c. it is converting mechanical energy to electrical energy.d. the electric current is always flowing in the same direction.


16. A motor’s basic function is to convert ____ to ____.a. electrical energy, mechanical energy.b. alternating current, direct current.c. mechanical energy, electrical energy.d. high voltage, low voltage.


17. The diagram below represents the rotor of an electric motor:

To cause the rotor to turn in a counter-clockwise direction, the north pole of a magnet should be placed at position:a. A.b. B.c. C.d. D.


18. The device that uses electromagnetic induction to produce electricity is called a:a. motor.b. rotor.c. turbine.d. generator.


19. When a magnet moves into a coil of wire, electric current is caused to flow by:a. conduction.b. reduction.c. induction.d. deduction.


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20. An electric generator produces:a. electrical energy.b. chemical energy.c. mechanical force.d. variable force.


21. According to Faraday’s law of induction, the faster a magnet is moved in and out of a coil:a. the greater the current produced.b. the less current produced.c. the greater the capacitance produced.d. the less capacitance is produced.


22. A transformer efficiently changes current and voltage:a. using electromagnetic induction.b. using alternating current.c. without changing power.d. All of the above


23. Electromagnetic induction occurs when:a. electromagnets are induced in a wire.b. electrons are induced in a magnet by a moving wire.c. current is induced in a wire by an moving magnet.d. a magnetic field is induced into a coil of wire by a current.


24. A current can be induced to flow in a coil in all of the following situations EXCEPT:a. holding a powerful magnet in the middle of a coil of wire.b. sliding a bar magnet into a coil of wire.c. moving a coil of wire toward an electromagnet.d. dropping a coil of wire over a bar magnet.


25. A generator’s basic function is to convert ____ to ____.a. electrical energy, mechanical energy.b. alternating current, direct current.c. mechanical energy, electrical energy.d. high voltage, low voltage.


26. The motion of a magnet that induces the greatest alternating current to flow in a coil is:a. rapid movement in one direction through the coil.b. rapid back and forth movement of the magnet in the coil.c. slow movement in one direction through the coil.d. no motion of the magnet.


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27. The battery charger for a rechargeable drill contains a transformer that converts 120-volt household voltage to the 6 volts required by the drill battery. If the primary coil of the transformer has 20 turns, how many turns are on the secondary coil?a. 20b. 6c. 2d. 1


28. A step down transformer has a primary voltage of 120 volts. The primary coil has 30 turns, and the secondary coil has 3 turns. The secondary voltage is ____ volts.a. 360b. 30c. 12d. 9


29. An alternating current is produced by an electric generator because the:a. chemical energy increases and decreases each turn.b. nuclear energy increases and decreases each turn.c. magnetic field increases and decreases each turn.d. magnetic field remains the same each turn.


30. You want to build a transformer that steps up voltage. You will need:a. more turns in the primary coil than the secondary coil.b. more turns in the secondary coil than the primary coil.c. the same number of turns in the primary and secondary coils.d. Not enough information given.


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Chapter 17: Electromagnets and Induction—Multi-format Bank

MODIFIED TRUE/FALSE

1. A solenoid is an electromagnetic device made of coils of wire with many turns. _________________________


2. The magnetic field is strongest outside a current-carrying coil of wire. _________________________

ANS: F, inside DIF: basic REF: section 17.1

3. A generator changes electrical energy to mechanical energy. __________________________

ANS: F, electric motor DIF: basic REF: section 17.2

4. The rotating element of a motor is referred to as the field coil. __________________________

ANS: F, armature DIF: basic REF: section 17.2

5. A transformer uses electromagnetic induction to change voltage and current without changing power. _________________________


COMPLETION

1. Two straight wires with their currents in the same direction ____________________ each other.

ANS: attract DIF: intermediate REF: section 17.1

2. A device that changes mechanical energy to electrical energy is a ____________________.

ANS: generator DIF: basic REF: section 17.3

3. ______________________________ (two words) occurs when current is induced in a wire by a moving magnet.

ANS: Electromagnetic induction DIF: basic REF: section 17.3

4. The current produced by a generator is always ____________________ current, which is commonly abbreviated as ____________________.

ANS: alternating, AC DIF: intermediate REF: section 17.3

5. An electric current can be made to flow if the magnetic field surrounding the wire is ____________________.

ANS: changing DIF: intermediate REF: section 17.3

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SHORT ANSWER

1. If a wire carrying electric current is looped into a coil, why is the magnetic field stronger inside the coil than outside the coil?

ANS: The magnetic fields through each coil add together, concentrating at the center of the coil.


2. What happens when you place a compass near a current-carrying wire?

ANS: The compass needle moves as if the wire were a magnet.


3. Describe the shape and strength of the magnetic field of a straight, current-carrying wire.

ANS: The magnetic field of a straight, current-carrying wire consists of concentric circles around the wire. The magnetic field is stronger closer to the wire.


4. What are two ways the magnetic field from current-carrying wires can be strengthened?

ANS: Any two of the following answers are correct.

1)Increase the amount of current in the wires.2) Decrease the distance to the wires.3) Bundle the wires.4) Coil the wires.


5. A bar magnet is suspended so that it is free to rotate. When you hold a second bar magnet near the suspended magnet, the suspended magnet begins to rotate. Explain what must be done to keep the magnet rotating.

ANS: To keep the magnet spinning, you need to reverse the hand-held magnet as each end of the suspended magnet comes by.


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6. What is the purpose of a commutator in an electric motor?

ANS: The commutator switches the polarity of the electromagnet from north to south and back again. Switching the polarity makes the rotor turn.


7. How can you induce current in a wire using a permanent magnet?

ANS: You can induce current either by moving the permanent magnet through a coil of wire or by moving a coil of wire over the permanent magnet.


8. What is the main difference between a motor and a generator?

ANS: A generator is used to convert mechanical energy to electrical energy, but a motor is used to convert electrical energy to mechanical energy.


PROBLEM

1. Describe the magnetic force between the two current-carrying wires shown in the diagram.

ANS: The wires repel each other.


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2. In which direction will the rotating disk spin?

ANS: Counterclockwise


3. On a European trip, you discover that the electric outlets have 240 volts. You realize that you need a transformer, so you quickly wrap 20 turns around the primary coil. If you need 120 volts to run your hairdryer, how many turns do you need to wrap around the secondary?

ANS: V2

V1

=N2

N1

240 volts120 volts

=N2

20

N2 =240 volts × 20

120 volts= 40 turns


4. A transformer has a primary voltage of 12 volts and a secondary of 120 volts. If the secondary coil has 100 turns, how many turns must the primary have?

ANS: V2

V1

=N2

N1

120 volts12 volts

=100N1

N1 =12 volts × 100

120 volts= 10 turns


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5. A transformer has an secondary voltage of 9 volts when connected to a 120-volt outlet. What is the ratio to the number of turns on the primary coil to the number of turns on the secondary coil?

ANS: V2

V1

=N2

N1

9 volts120 volts

=N2

N1

N2

N1

= 0.075

N1

N2

= 13.3


ESSAY

1. Name 3 advantages an electromagnet has over a permanent magnet.

ANS: Answers may vary. Correct answers include:1. The direction of the poles can be reversed by changing the direction of the current in its coil.2. The magnet’s strength can be altered by changing the amount of current flowing in its coil.3. The electromagnet can be turned off and on again.4. Electromagnets can be easily designed to be stronger than permanent magnets.


2. List the 3 key components from which all electric motors are made.

ANS: 1. A rotating magnetic element, the rotor.2. A stationary magnet that surrounds the rotor.3. A commutator that switches the electromagnets’ polarity to maintain the rotor’s motion.


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3. Explain how an electric motor works. Be sure to use the words rotor, commutator, permanent magnets, and electromagnets.

ANS: A motor has a spinning disk called a rotor. When the rotor is spinning, the motor can do useful work. The rotor has magnets along its outside edge. In some motors, these are permanent magnets. Other motors use electromagnets. Outside the rotor there is another magnet (or set of magnets). A commutator causes the magnet to reverse its polarity from north to south and back again. As the polarity changes, the magnets in the rotor are first attracted and then repelled by the “outer” magnet. This action is similar to the pull-and-then-push action that we use to turn a merry-go-round. The attracting and repelling action of the outer magnet causes the rotor to turn.


4. List the 3 ways to increase the induced voltage in a generator.

ANS: 1. Increase the number of turns of wire in the rotating coil.2. Increase the coil’s speed through the magnetic field.3. Increase the magnetic field’s strength through which the coil moves.


5. What did Michael Faraday discover about the relationship between electricity and magnetism?

ANS: Michael Faraday discovered that the current created in a coil is proportional to the rate of change of the magnetic field through the coil.


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Chapter 18: Fields and Forces—Multiple Choice Bank

MULTIPLE CHOICE

1. All of the following are types of fields EXCEPT:a. gravity.b. light.c. magnetism.d. mass.


2. The strength of a field:a. decreases the farther you get from the source.b. increases the farther you get from the source.c. stays the same throughout.d. varies randomly throughout.


3. The strength of a magnetic field compared to an electric or gravitational field:a. increases more quickly as you get farther from the source.b. decreases more quickly as you get farther from the source.c. is identical.d. None of the above


4. The force of gravity you feel from Earth reaches you through:a. Earth’s magnetic field.b. Earth’s core.c. Earth’s gravitational field.d. electromagnetic waves.


5. What type of field surrounds a moving charged particle?a. Electric field onlyb. Magnetic field onlyc. Gravitational field onlyd. All of the above


6. If an object with a charge of 0.05 coulombs experiences an electric force of 5 newtons, the electric field strength in newtons/coulomb is ____ N/C.a. 0.01b. 0.25c. 100d. 500


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7. Gravitational fields and electric fields are similar in all the following ways EXCEPT:a. their intensities follow an inverse square law.b. they are both vector fields.c. they are both force fields.d. they both are created by mass.

ANS: D DIF: intermediate REF: section 18.1, section 18.2, section 18.3

8. How does the intensity of light 2 meters from a light bulb compare to the intensity 4 meters away from the light bulb?a. It is 2 times more intense.b. It is 2 times less intense.c. It is 4 times more intense.d. It is 4 times less intense.


9. The fastest speed a field can spread forces, energy, or information is ____ m/sec.a. 100,000b. 300,000,000c. 9.8d. There is no limit to the speed.

ANS: BThe speed of light


Figure 12-2AThe distance between the sun and Earth is 1.5 × 1011 meters.The mass of the sun is 1.99 × 1030 kg.The radius of the sun is 6.9 × 108 meters.Answer the following questions about the sun-Earth system.

10. Referencing the information in Figure 12-2A, how long does it take the light produced by the sun to travel to your eyes on Earth?a. 0.002 secondsb. 4.5 × 1019 secondsc. 500 secondsd. instantly

ANS: C

time =distancespeed

=1.5 × 1011 m

3 × 108 m/sec= 500 sec


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11. Referencing Figure 12-2A, if the sun were to explode, how long would it be before the explosion would be seen on Earth?a. 0.002 secondsb. 4.5 × 1019 secondsc. 500 secondsd. instantly


12. Referencing Figure 12-2A, if the sun were to explode and vanish, which of the following would happen to Earth?a. Earth would immediately explode and vanish.b. Earth would fly out of its orbit after a 500-second delay.c. Earth would fly out of its orbit immediately.d. No change would happen.


13. Referencing Figure 12-2A, the gravitational field strength due to the sun at the surface of Earth is ____ N/kg.a. 9.8b. 8.9 × 108

c. 7.5 × 10-19

d. 0.006


14. Referencing Figure 12-2A, the gravitational field (value of g) on the surface of the sun is ____ N/kg.a. 1.9 × 1011

b. 6.67 × 10-11

c. 279d. 9.5 × 1047


15. The gravitational field (value of g) at the surface of a 0.045 kg golf ball with a radius of 0.021 meters is ____ N/kg.a. 6.67 × 10-11

b. 1.4 × 10-10

c. 9.8d. 6.8 × 10-9


16. What creates an electric field?a. Drift speedb. The forces between charged particlesc. Magnetic attractionsd. The forces between masses


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17. What happens to an electric field as you get farther away from the charge that creates the field?a. It changes to a magnetic field.b. It decreases.c. It increases.d. None of the above


18. The electric field inside a conductor that is not carrying current is:a. increasing.b. zero.c. positive.d. negative.


19. Electric field lines always point:a. away from positive charge and toward negative charge.b. toward positive charge and away from negative charge.c. across each other.d. to the inside of a conductor.


20. Placing a conductor into an electric field creates a:a. shielding effect with no electric field inside the conductor.b. current inside the conductor.c. negative charge inside the conductor.d. positive charge inside the conductor.


21. The force in newtons of an electric field of strength 2.0 newtons/coulomb on a positive charge of 0.5 coulombs is ____ N.a. 0.25b. 0.5c. 1.0d. 4.0


22. An object with charge of 5 × 10-9 C experiences an upward force of 20 × 10-9 N when placed at a certain point in an electric field. The electric field strength at that point is ____ N/C.a. 0.25b. 4.0c. 100d. 4 × 10-9


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23. Which of the following diagrams is NOT a possible representation of an electric field?

a. c.

b. d.


24. An electric field has a strength of 2 volts/meter. It exerts a force of ____ N on a positive charge of 0.002 coulombs.a. 9.8b. 0.004c. 1,000d. 0.001

ANS: BF = qE = 0.002 C × 2 V/m = 0.004 N


25. A negative charge of 0.01 coulombs is in a 200 volts/meter electric field. The force on the charge is ____ newtons.a. 9.8b. 2c. 20,000d. 5 × 10-5

ANS: BF = qE = 0.01 C × 200 V/m = 2 N


26. Which of the following is a unit used to measure the strength of an electric field?

a.voltsmeter

c.kilograms ×meters

seconds2 × coulombs

b.newtonscoulomb

d. All of the above


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27.

The graph represents the relationship between electric force and the charge of an object. The slope of the graph represents:a. the strength of the electric field.b. Coulomb’s constant, k = 9 × 109 N×m2/C2.c. momentum.d. voltage.


28. The electric field around two positive charges looks most like:

a. c.

b. d.


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Chapter 18: Fields and Forces—Multi-format Bank

MODIFIED TRUE/FALSE

1. The fastest speed a field can spread information, force, or energy is the speed of light. _________________________


2. A gravitational field is an example of a force field. _________________________


3. As you move farther away from a positive electric charge, the electric field becomes stronger. _________________________

ANS: Fweakerless strong


4. The forces between charged particles create gravitational fields. _________________________

ANS: F, electric DIF: basic REF: section 18.3

5. You can tell the strength of an electric field by how close together the field lines are. __________________________


COMPLETION

1. The relationship between force and distance in both electric fields and gravitational fields is called a(n) _________________________ (three words).

ANS: inverse square law DIF: intermediate REF: section 18.1

2. Gravitational fields are created by ____________________.

ANS: mass DIF: basic REF: section 18.2

3. The moon is held in orbit around Earth because of the force exerted by Earth’s ________________________ (two words).

ANS: gravitational field DIF: basic REF: section 18.2

4. A(n) ____________________ field surrounds a moving charged particle.

ANS: electric DIF: basic REF: section 18.3

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5. The magnitude of the electric field within a conductor not carrying a current is ____________________.

ANS: zero0


SHORT ANSWER

1. List two different types of fields and describe what creates them.

ANS: Answers will vary. Any two of the following answers are correct:Gravitational fields are created by mass.Electric fields are created by charged particles.Magnetic fields are created by moving electrical currents.Sound fields are created by sound.Temperature fields are created by temperature.Light fields are created by light.Radio wave fields are created by radio waves.


2. Describe what happens in a gravitational field as you get further away from the mass that creates the field.

ANS: The field decreases inversely with the square of the distance from the source.


3. How does the strength of a gravitational field 3 meters away from its source compare to the strength of the field 9 meters away from the source?

ANS: The field is 9 times stronger at 3 meters than at 9 meters due to the inverse square law.


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4. What two units can be used to measure the strength of an electric field?

ANS: Any two of the following three answers are correct.1) newtons per coulomb (N/C)2) volts per meter (V/m)

3) kilograms ×meters

seconds2 × coulombs


PROBLEM

1. What is the gravitational field (value of g) on the surface of the planet Venus? Venus has a mass of 4.9 × 1024 kilograms and a radius of 6.05 × 106 meters.

ANS:

g =Gm 2

r2 =6.67 × 10−11 N ⋅m2 / kg2Ê

ËÁÁÁ

ˆ¯˜ 4.9 × 1024 kgÊËÁÁÁ

ˆ¯˜

6.05 × 106 mÊËÁÁÁ

ˆ¯˜

2 = 8.92 N/kg


2. The moon has a mass of 7.3 × 1022 kilograms and is 384,000,000 meters away from Earth. What is the gravitational field strength due to the moon at Earth’s surface?

ANS:

g =Gm1

r2 =6.67× 10−11 N ⋅m2 / kg2Ê

ËÁÁÁ

ˆ¯˜ 7.3 × 1022 kgÊËÁÁÁ

ˆ¯˜

3.84× 108 mÊËÁÁÁ

ˆ¯˜

2 = 3.3 × 10−5 N/kg


3. An electric field has a strength of 1.5 volts/meter. What force does it exert on a negative charge of 0.00002 coulombs?

ANS: F = qE = 0.0002 C × 1.5 V/m = 0.0003 N


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4. A positive charge of 0.2 coulombs experiences a 2-newton electric force. What is the strength of the electric field?

ANS:

E =Fq=

2 N0.2 C

= 10 volts/meter (or 10 N/C)


ESSAY

1. Describe one difference and one similarity between gravitational fields and electric fields.

ANS: Differences (any one of the following answers is correct):1) Gravitational fields are created by mass while electric fields are created by charges.2) Gravitational fields are generally much weaker than electric fields.

Similarities (any one of the following answers is correct):1) The field strengths of both obey an inverse square law.2) Both are force fields.3) Both are vector fields.4) Both carry forces at the speed of light.


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Chapter 19: Harmonic Motion—Multiple Choice Bank

MULTIPLE CHOICE

1. Motion that occurs in repeated cycles includes all of the following EXCEPT ____ motion.a. pendulumb. harmonicc. lineard. circular


2. A unit of motion repeated over and over again is called the:a. amplitude.b. cycle.c. velocity.d. period.


3. Oscillating systems include all of the following EXCEPT:a. the moving pedals on a bicycle.b. a radio signal from FM station 106.3.c. Earth turning on its axis.d. a block sliding down a ramp.


4. The measure of the number of cycles per second is called:a. frequency.b. period.c. amplitude.d. vibration.


5. The unit for measuring the frequency of an oscillating system is the:a. meter.b. meter/second.c. hertz.d. hertz/second.


6. The amount of time required for one cycle to occur is called the:a. amplitude.b. frequency.c. harmonic.d. period.


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7. A unit used to measure the period of a cycle is the:a. second.b. hertz.c. meter.d. newton-second.


8. In a mechanical system, the distance an oscillator moves from its average position is called:a. amplitude.b. cycle.c. frequency.d. period.


9. The reason an oscillator may be used to keep time is the:a. amplitude of each cycle is uniform.b. period of each cycle is the same.c. frequency of its vibration changes.d. period of its cycle can be adjusted.


10. A pendulum makes one complete swing over and back in 2.2 seconds. Its frequency is:a. 0.45 hertz.b. 0.45 seconds.c. 2.2 hertz.d. 2.2 second.


11. An insect moves its wings up and down 144 times in three seconds. The period of this movement is:a. 0.0208 seconds.b. 48 hertz.c. 48 seconds.d. 144 hertz.


12. A string is vibrating at a frequency of 440 hertz. If the frequency is doubled, what happens to the period?a. The period decreases by 1/4.b. The period decreases by 1/2.c. The period remains the same.d. The period doubles.


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13. When damping occurs in a moving pendulum system, it may cause the:a. mass of the pendulum to decrease.b. amplitude of the pendulum to decrease.c. length of the pendulum to increase.d. period of the pendulum to decrease.


14. A sound wave is transmitted as the compression and expansion of air. Which of the following represents one cycle of harmonic motion for a sound wave?a. A region of high pressure and low pressureb. A region of high pressurec. A region of low pressured. Sound waves do not have cycles of motion.


15. The diagram below represents a graph of harmonic motion:

One cycle of the motion is represented by the distance from:a. A to B.b. B to D.c. B to E.d. A to E.


16. A graph of harmonic motion shows that a cycle lasts 8.0 seconds. What is the frequency of this oscillator?a. 0.125 hertzb. 0.125 secondsc. 8.0 hertzd. 8.0 seconds


17. The period of a pendulum multiplied by its frequency (T × f ) equals:a. one amplitude.b. one cycle.c. the number one.d. one swing.


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18. Assuming that it takes exactly 24 hours for Earth to rotate on its axis, the frequency of rotation of Earth measured in hertz is:a. 0.125 secondsb. 0.042 hertz.c. 1400 hertz.d. 86000 hertz.


19. The unit most frequently used to measure the phase relationship between parts of the cycle of an oscillator is the:a. hertz.b. meter.c. degree.d. second.


20. One full cycle of harmonic motion is represented by ____ degrees.a. 45b. 90c. 180d. 360


21. Two oscillators that are 180 degrees out of phase are:a. one-quarter of a cycle apart.b. one-half of a cycle apart.c. three-quarters of a cycle apart.d. one full cycle apart.


22. The graph below represents position versus time for the amplitude of a pendulum that was allowed to swing for four seconds:

Which letter correctly identifies the amplitude of the pendulum?a. Ab. Bc. Cd. D


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23. The diagram below represents a segment of a periodic wave:

Which two points represent the same point in a cycle?a. C and Ib. A and Dc. B and Ed. C and H


24. One cycle of harmonic motion for a certain spring takes 6 seconds. If a second, identical spring is set in motion 4 seconds after the first, the phase relationship between the motion of the two springs differs by ____ degrees.a. 67b. 75c. 240d. 270


25. The diagram represents the harmonic motion of two identical, vibrating springs:

The phase relationship of the two springs differs by approximately ____ degrees.a. 90b. 180c. 270d. 360


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26. Resonance occurs for a system in harmonic motion when the:a. frequency of the periodic force is larger than the natural frequency of the system.b. frequency of the periodic force equals the natural frequency of the system.c. frequency of the periodic force is less than the natural frequency of the system.d. Resonance cannot occur for a system in harmonic motion.


27. If you triple the mass on a pendulum bob, the period of the pendulum:a. increases by 3 times.b. decreases by 1/3.c. does not change.d. increases by 1/3.


28. The force that brings the motion of an oscillator toward its equilibrium position is called its ____ force.a. gravitationalb. strongc. restoringd. centripetal


29. You can change the natural frequency of a pendulum by changing the:a. mass of the pendulum bob.b. length of the pendulum string.c. amplitude of the restoring force.d. The natural frequency of a pendulum cannot be changed.


30. As an oscillating spring is moved farther from its equilibrium position, the:a. energy does not change.b. amplitude decreases.c. period increases.d. restoring force increases.


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Chapter 19: Harmonic Motion—Multi-format Bank

MODIFIED TRUE/FALSE

1. An object is an oscillator if it exhibits linear motion. _________________________

ANS: Fperiodicharmoniccircular


2. A unit of motion that repeats over and over again is a phase. _________________________

ANS: F, cycle DIF: basic REF: section 19.1

3. The frequency of an oscillator is inversely related to its amplitude. _________________________

ANS: F, period DIF: basic REF: section 19.1

4. The number of degrees in one complete cycle of oscillation is 360 degrees. _________________________


5. Increasing the length of a pendulum causes its period to decrease. _________________________

ANS: F, increase DIF: basic REF: section 19.3

COMPLETION

1. Stringed instruments, systems involving Earth, and pendulums all act as ____________________.

ANS: oscillators DIF: basic REF: section 19.1

2. The unit representing one cycle per second is called the ____________________.

ANS: hertz DIF: basic REF: section 19.1

3. The time required for a pendulum to make one swing over and back is called its ____________________.

ANS: period DIF: basic REF: section 19.1

4. The gradual loss of amplitude by an oscillating system due to friction is known as ____________________.

ANS: damping DIF: basic REF: section 19.1

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5. The maximum distance a mechanical oscillator moves from its equilibrium position is called its ____________________.

ANS: amplitude DIF: basic REF: section 19.1

6. Harmonic motion is the result of a restoring force bringing an oscillator to the ____________________ position.

ANS: equilibriumcenter


SHORT ANSWER

1. List three ways in which Earth might be considered to be part of an oscillating system.

ANS: Answers may vary. Correct answers include:The moon revolving about Earth about once a month.The Earth rotating on its axis approximately once every 24 hours.The Earth wobbling on its axis, completing a cycle every 22,000 years.The Earth revolving about the Sun every 365.25 days.


2. Why is harmonic motion useful for time keeping?

ANS: Harmonic motion is useful for time keeping because each cycle takes the same amount of time. The time for each cycle is called a period.


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3. Point A is shown on the harmonic motion graph of a vibrating string. Another point is located 1/2 of a phase away from point A. Which point on the graph shows the position of the second point?

ANS: Point C


4. The diagram below represents the graph produced from the motion of two oscillators A and B. What is the phase difference measured in degrees between A and B?

ANS: 90 degrees


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5. The diagram below shows sound transmitted as the compression and expansion of air molecules, an example of harmonic motion. Labeling the diagram with X’s, show the distance that represents one cycle.

ANS: The X’s should be placed so that the second X is in the same relative position on one wave as the first X placed on the diagram. For example:


6. What is the meaning of the term restoring force? In what direction does it always move?

ANS: The restoring force is a force that always acts to bring an oscillator back toward the equilibrium position. It is always directed toward the center of oscillation.


7. List three ways to change the natural frequency of a guitar’s “A” string.

ANS: Answers may vary. Correct answers include:Changing the length of the guitar, or use a different guitar.Tightening or loosening the string by tuning it.Touching the string, which effectively shortens it.Changing the thickness of the string.Changing the material from which the string is made.Changing the temperature or humidity (which might affect tension or the length of the string).


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PROBLEM

1. If a bumble bee flaps its wings at a frequency of 130 beats per second, what is the period of vibration of the bee’s wings?

ANS:

period =1

frequency=

1130 Hz

period = 0.0077 seconds


2. If your heart beats at a rate of 65 beats per minute, what is the frequency of your heart measured in hertz?

ANS: 1 Hz = 1 cycle (or 1 beat) per second

frequency = 65beats

minute×

1 minute60 sec

= 1.1beatssec

frequency = 1.1 hertz


3. The distance between the highest and lowest position for an oscillator on a graph of harmonic motion is 40 centimeters. What is the amplitude of the oscillator?

ANS: 20 centimetersAmplitude is one-half the distance from the highest to the lowest points on the graph of harmonic motion. The amplitude is 20 centimeters.


4. An oscillator with a frequency of 0.25 hertz is set in motion. One second later, an identical oscillator is set in motion. What is the phase separation of these two oscillators?

ANS: 90 degrees out of phase.

period of 1st oscillator =1

frequency=

10.25 Hz

= 4 seconds

The second oscillator is set in motion 1 second (or 1

4 of a period) later, causing it to “lag behind” by

1

4

of a period or 90 degrees.


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5. Using the diagram below, sketch a graph that represents the motion of a harmonic oscillator whose frequency is 2.0 hertz and amplitude is 0.2 meters.

ANS: Answer may vary. The diagram shows one possible answer. An explanation follows:

Since the frequency of the oscillator is 2.0 hertz, the period is 0.5 seconds. One cycle is completed in 0.5 seconds. The diagram should picture a graph with a cycle extending from 0.0 seconds to 0.5 seconds, 0.5 to 1.0 seconds, 1.0 to 1.5 seconds and the wave height extending above and below the zero line 0.2 meters. Four complete oscillations can be pictured on the blank graph provided.


ESSAY

1. “Circular motion represents harmonic motion.” Explain why that statement might be considered a correct statement.

ANS: Circular motion involves continuous rotation of an object. For example, for the motion of a rotating wheel, one cycle would be the time it takes to go one full circle or 360 degrees. On a harmonic motion graph, the circular motion of the wheel and the motion of a pendulum have a similar shape.


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2. How could you change the natural frequency of a pendulum?

ANS: Natural frequency depends on the balance between the restoring force and the inertia (or mass). Changing the length of the string will change the natural frequency - increasing the length will increase the period and decreasing the length will decrease the period. Changing the mass of the bob or the amplitude of the pendulum does NOT change the period or affect the natural frequency since the restoring force of a pendulum is due to gravity.


OTHER

1. Laser light is the result of harmonic motion in which all oscillations produced are in phase. Which diagram below best represents laser light?

ANS: #4


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Chapter 20: Waves—Multiple Choice Bank

MULTIPLE CHOICE

1. The term antinode is another name for the:a. fundamental frequency of an object.b. harmonics of a vibrating string.c. depression on a standing wave.d. “bump” on a standing wave.


2. Multiples of the fundamental frequency of a vibrating string are called:a. harmonics.b. amplitudes.c. interferences.d. nodes.


3. Which of the following is NOT a property of waves?a. Frequencyb. Amplitudec. Speedd. Weight


4. Under ordinary circumstances, a ____ wave is the slowest wave.a. lightb. radioc. soundd. water


5. The product of the frequency and the length of a wave yields its:a. period.b. amplitude.c. cycle.d. speed.


6. A sound wave, generated at a frequency of 440 hertz has a wavelength of 2.3 meters as it travels through a solid material. The approximate speed of the wave is ____ m/sec.a. 140b. 190c. 760d. 1,000


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7. Vibrating strings and similar systems have resonance patterns that occur at:a. frequency intervals of 12 hertz.b. amplitude intervals of one meter.c. multiples of the fundamental frequency.d. frequency intervals equal to wave speed times wavelength.


Figure 20-1A

The diagram represents a wave pattern in a certain medium. Answer the following questions based on the diagram.

8. Referring to Figure 20-1A, the wavelength in the diagram is represented by the distance from:a. A to D.b. B to C.c. D to F.d. F to G.


9. Referring to Figure 20-1A, the distance from point A to point G is 6.0 meters. If the speed of the wave is 330 meters per second, the frequency of this wave is ____ Hz.a. 55b. 165c. 660d. 1,980 Hz


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10. A student does an experiment with a string vibrating at 20 hertz and observes the resonance pattern shown in the diagram:

The speed of the wave on the string is ____ m/sec.a. 4.0b. 8.0c. 20d. 100


11. The wavelength of a certain frequency of light is 5 × 10-7 meters. If the speed of light is 300,000 km/sec, the frequency of the light is ____ hertz.a. 1.67 × 10-15

b. 1.67 × 10-12

c. 6.00 × 1011

d. 6.00 × 1014

ANS: Dspeed of light = 300,000 km/sec × 1,000 m/km = 3 × 108 m/sec

frequency =speed

wavelength=

3 × 108 m/sec5 × 10−7 m

= 6 × 1014 hertz


12. The bending of a wave front around a barrier is called:a. reflection.b. refraction.c. diffraction.d. absorption.


13. If your fingertip repeatedly touches the surface of water in a container at regular intervals, the action will produce:a. planes waves.b. circular waves.c. crests only.d. troughs only.


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14. The diagram represents a wave interaction as wave fronts pass through a small opening. This is an example of:

a. diffraction.b. refraction.c. reflection.d. absorption.


15. As a wave front crosses a boundary between two different media, the wave front may change direction, an interaction known as:a. reflection.b. refraction.c. diffraction.d. absorption.


16. Theaters often use heavy curtains to reduce echoes during performances. The function of the curtains is to ____ sound.a. refractb. reflectc. diffractd. absorb


17. Diffraction causes waves to:a. bounce off hard surfaces.b. spread out through small openings.c. become smaller as they move.d. increase their frequency.


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18. The process by which the amplitude of waves is reduced as a wave loses energy while moving through a substance is called:a. reflection.b. diffraction.c. absorption.d. refraction.


19. The direction a wave moves is:a. parallel to the wave fronts.b. perpendicular to the wave fronts.c. in the direction of increasing amplitude.d. in the direction of decreasing frequency.


20. You are still able to hear sounds coming from a room when the door is open only a tiny crack due to:a. reflection.b. refraction.c. diffraction.d. absorption.


21. Waves are affected by boundaries. When a wave front meets a certain boundary, all of the following may occur EXCEPT a change:a. of direction.b. in the pattern of the wave front.c. of frequency.d. of amplitude.


22. Two large waves on the ocean come together on the ocean’s surface to form a gigantic wave. The interaction responsible for this is called:a. frequency amplification.b. constructive interference.c. destructive interference.d. amplitude destruction.


23. Devices like a guitar, a piano, and a microwave oven function using controlled:a. standing waves.b. destructive interference.c. frequency amplification.d. amplitude reduction.


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24. Resonance in waves is created by:a. longitudinal waves only.b. constructive interference with a wave’s own reflections.c. diffraction of a wave around an object.d. absorption as a wave crosses a boundary.


25. The natural frequency of a guitar string can be changed using any of the following means EXCEPT:a. increasing the length of the string.b. plucking the string with greater force.c. increasing the thickness of the string.d. decreasing the length of the string.


26. Which wave interaction could be demonstrated by a single wave pulse?a. A standing waveb. Reflectionc. Constructive interferenced. The superposition principle


27. Which pair of moving pulses in a rope will produce destructive interference?

a. Ab. Bc. Cd. D


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28. Two pulses are traveling along a string toward each other as represented in the diagram below:

Which phenomenon will occur as the pulses meet?a. Interferenceb. Diffractionc. Reflectiond. Refraction


29. Maximum destructive interference between two waves will occur when the waves are out of phase by ____ degrees.a. 45b. 90c. 180d. 360


30. Which pair of waves produces a resultant wave with the largest amplitude?

a. Ab. Bc. Cd. D


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31. Maximum constructive interference between two waves of the same frequency could occur when their phase difference is:

a.3λ2

c.λ4

b.λ2

d. λ


32. For a standing wave to form in a medium, two waves must:a. travel in the same direction.b. have different wavelengths.c. have the same frequency.d. have different amplitudes.


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Chapter 20: Waves—Multi-format Bank

MODIFIED TRUE/FALSE

1. A sound wave is an example of a longitudinal wave. _________________________


2. The function of a wave is to carry oscillations from one place to another. _________________________


3. When a wave bounces off a wall and changes direction, its interaction with the wall is called diffraction. ________________________

ANS: F, reflection DIF: basic REF: section 20.2

4. A wave is absorbed when it bends as it passes through a boundary. _________________________

ANS: F, refracted DIF: basic REF: section 20.2

5. As the frequency of a vibrating string increases, the wavelength increases. _________________________

ANS: F, decreases DIF: basic REF: section 20.3

COMPLETION

1. The product of the frequency and the length of a wave yields its ____________________.

ANS: speedvelocity


2. In one complete cycle, a wave moves forward one ____________________.

ANS: wavelength DIF: basic REF: section 20.1

3. A wave whose oscillations are perpendicular to the direction in which the wave travels is called a ____________________ wave.

ANS: transverse DIF: basic REF: section 20.1

4. The distance from one point on a wave to the same point on the next wave is called the ____________________.

ANS: wavelength DIF: basic REF: section 20.1

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5. Another name for the natural frequency of a vibrating string is the: ____________________.

ANS: fundamental DIF: basic REF: section 20.1

6. Pushing the water in a container with a ruler makes a ____________________ wave.

ANS: plane DIF: basic REF: section 20.2

SHORT ANSWER

1. List the following waves in order of their speeds from fastest to slowest and give their approximate speed.a. sound wavesb. light wavesc. water waves

ANS: sound: 600 miles per hour, 1,000 km/hr, 300 m/seclight: 186,000 miles/sec, 300,000 km/sec, 300,000,000 m/secwater: a few miles per hour, a few kilometers per hour


2. How many waves are represented in this diagram?

ANS: 4 1/2


3. A vibrating string produces a standing wave of the 5th harmonic. How many wavelengths are contained in this standing wave?

ANS: 2 1/2


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4. List four things that may happen to a wave as it meets a boundary.

ANS: reflectionrefractiondiffractionabsorption


PROBLEM

1. Middle C on a piano has a frequency of about 264 hertz. If the wavelength in air of this note is 1.31 meters, what is the speed of sound in air?

ANS: 346 m/secspeed = frequency ×wavelength = 264 Hz× 1.31 m = 346 m/sec


2. On a July day, the waves in the Outer Banks of North Carolina hit the beach every 13 seconds. If the distance between each wave crest is 25 meters, what is the speed of the waves as they travel toward the beach?

ANS: 1.9 m/sec

speed =wavelength

period=

25 m13 sec

= 1.9 m/sec


3. The magnetron of a microwave oven produces a standing, electromagnetic wave with a frequency of 2.4 × 109 cycles per second. What is the length of one of these standing waves if the speed of an electromagnetic wave is 3.0 × 108 m/sec?

ANS: 1.25 × 10-1 meters (or 0.125 meters)

wavelength =speed

frequency=

3 × 108 m/sec2.4 × 109 Hz

= 1.25 × 10−1 meters


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4. A string 3.0 meters long is vibrating at 50 hertz at the 4th harmonic. Calculate the speed of the wave on the string.

ANS: 75 meters/secondFrequency is given as 50 hertz. In the 4th harmonic, there are two complete waves on the 3.0 meter string. Wavelength is therefore 1.5 meters.

speed = frequency×wavelength = 50 hertz× 1.5 m = 75 m/sec


ESSAY

1. A string one meter long is being driven to vibrate at its fundamental frequency. The driver frequency is increased, causing the string to vibrate at its second harmonic. Explain what happens to the speed of the wave on the string when the frequency is increased.

ANS: Nothing. As the frequency increases (doubles), the wavelength undergoes a decrease by the same factor (becomes 1/2 of the previous wavelength). Since the product of frequency times wavelength equals the speed, increasing one and decreasing the other by the same factor causes no change in the product, the speed.


2. Describe each of the following using at least one complete sentence.a. reflectionb. refractionc. diffractiond. absorption

ANS: a. Reflection occurs as a wave meets a boundary and bounces off (is turned back at) the boundary in a new direction.

b. Refraction occurs as a wave moves through a boundary. The wave may change direction.

c. Diffraction occurs as a wave travels around an obstacle or through a small opening at a boundary. The direction of the wave front is altered.

d. Absorption occurs as a medium takes up some of the energy of a wave upon entering the medium. As a result, the amplitude of a wave continues to decrease as it passes farther into the new medium.


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3. Explain why a hot dog on a dry paper plate becomes hot in a microwave oven but the paper plate becomes hot only where it is in contact with the hot dog.

ANS: The microwave oven produces a wave that matches the resonant frequency of water molecules. The energy of the wave is absorbed by the water molecules and manifests itself as heat. The hot dog contains water; it becomes hot since it is in contact with the heated water molecules. The paper plate does not contain water, so it becomes hot only where it touches the “hot” hot dog.


OTHER

1. The diagram represents a 2-meter long string fastened securely at the right end. The string is being driven to vibrate from the left end. Answer the questions below based upon this diagram:

a. What harmonic is represented by the diagram? ____________________b. What is the wavelength of the vibrating string? ____________________c. Label ALL points representing nodes with the letter “N”.d. Label ALL points representing antinodes with the letter “A”.

ANS: a. 3rd

b. 1.33 metersc. and d.(See diagram below)


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2. Identify the wave interaction represented by each diagram.a.

b.

c.

ANS: a. refractionb. reflectionc. diffraction


3. Two pulses are traveling on a rope as shown in the diagram. The two pulses meet for an instant.

a. Name the type of interference that occurs at that instant.b. Draw a diagram that would represent the rope at the instant the pulses meet.

ANS: a. constructiveb. (See diagram below)


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Chapter 21: Sound—Multiple Choice Bank

MULTIPLE CHOICE

1. The musical term “pitch” is most directly proportional to:a. amplitude.b. volume.c. wavelength.d. frequency.


2. The loudness of sound is measured in units called:a. newtons.b. pascals.c. hertz.d. decibels.


3. Ordinary conversation, measured in decibel units, would be most nearly ____ dB.a. 15b. 65c. 100d. 125


4. The term applied to objects that travel at speeds exceeding the normal speed of sound in air is:a. subsonic.b. supersonic.c. sonogram.d. reverberation.


5. As the decibel level increases from 20 decibels to 40 decibels, the loudness of the sound is described as:a. 10 times louder.b. 2 times louder.c. 10 times quieter.d. 2 times quieter.


6. Due to the Doppler effect, the pitch of the siren of a fire truck moving away from you:a. decreases.b. increases.c. increases then decreases.d. does not change.


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7. The four diagrams below represent the amplitude of sounds produced versus time. Which diagram represents a complex sound?

a. c.

b. d.


8. Sound will travel:a. faster in air than in any material.b. fastest in outer space.c. faster in steel than in air.d. faster in cold air than warm air.


9. According to the Equal Loudness Curve graph, as the frequency of a sound decreases from 2,000 hertz to 50 hertz, the human ear’s sensitivity to the loudness of that sound:

a. increases.b. decreases.c. is equal.d. depends on the source.


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10. You yell across the bottom of a wide canyon and hear your echo 3 seconds later. The approximate width of the canyon producing the echo is ____ meters.a. 1,000b. 500c. 300d. 100


11. Ultrasound is useful for all of the following EXCEPT:a. examining a beating heart.b. placing mp3 files on a CD.c. detecting structural damage in materials.d. determining the gender of an unborn child.


12. A large explosion generally can be “felt” some distance away and is the source of a low frequency sound because it causes a variation in the:a. air temperature.b. air pressure.c. mass of air molecules.d. weight of air molecules.


13. Sound shows wave characteristics for all of the following reasons EXCEPT:a. the mass of sound increases as its frequency increasesb. sound may be reflected and refractedc. the speed of sound is the product of frequency and wavelengthd. sound shows evidence of diffraction and interference


14. The speed of sound in air at normal temperatures is about ____ m/sec.a. 34.b. 340c. 3,400d. 34,000


15. The speed of sound is affected by all of the following EXCEPT:a. decibel level.b. air pressure.c. temperature.d. weight and size of the molecules it travels through.


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16. Which of the following statements about reverberations is INCORRECT?a. Reverberations may create dead spots in a large room.b. Reverberations may cause loud spots in a large room.c. Reverberations are caused by absorption of sound by concert hall walls and ceilings.d. The source of reverberation is multiple echoes from concert hall walls and ceilings.


17. The oscillation of air pressure can result in ____ waves.a. transverseb. lightc. longitudinald. circular


18. Large horns such as tubas produce sounds with long wavelengths while flutes produce sounds with short wavelengths because:a. the frequency of sound produced is directly proportional to the size of the instrument.b. the wavelength of sound produced is directly proportional to the size of the instrument.c. the wavelength of sound produced is directly proportional to the frequency.d. the pitch of the sound produced is directly proportional to the wavelength.


19. Which of the following has the shortest wavelength?a. A rumble of thunder at 20 hertzb. An average male singer at 500 hertzc. The highest note on a piano at 5,000 hertzd. The whine of a jet turbine at 10,000 hertz.


20. The marching band is practicing behind the school. In front of the school, students are able to hear the band because the sound waves are:a. absorbed by the building and trees.b. diffracted over and around the school.c. refracted by the school building.d. enhanced by destructive interference.


21. On the Fourth of July, you can see large fireworks displays before you hear them because the speed of light exceeds the speed of sound by about ____ times.a. 10b. 1,000c. 100,000d. 1,000,000


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22. The perception of sound starts with the:a. stimulation of the fluid in the cochlea.b. response of short hairs of the ear canal.c. movement of three delicate bones of the inner ear.d. vibration of the eardrum.


23. The term for a regular time pattern in sound is:a. rhythm.b. pitch.c. scale.d. harmony.


24. The musical effect based upon the relationship between frequencies can be called:a. pitch.b. harmony.c. beats.d. rhythm.


25. Musicians may tune their instruments to match a certain frequency by adjusting the frequency they play to eliminate:a. scales.b. rhythm.c. pitch.d. beats.


26. The property of sound that most helps you to identify one person’s voice from another is:a. decibels.b. beats.c. harmonics.d. scales.


27. A piano and a guitar playing the same “C” note sound different because pianos:a. produce sound with more decibels.b. and guitars produce different combinations of frequencies.c. produce pure frequencies but guitars do not.d. have more “strings”(wires) to vibrate than guitars.


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28. A special graph of sound displaying the frequency versus time while indicating how loud the sound is at various frequencies is called a(n):a. sonogram.b. equal loudness curve.c. ultrasound.d. spectrum..


29. A combination of frequencies which sounds bad or is unsettling is called:a. dissonance.b. consonance.c. harmony.d. pitch.


30. While a young child is able to hear frequencies of sound up to 20,000 hertz, the highest frequency an average adult is able to hear is:a. 2,000 hertz.b. 5,000 hertz.c. 15,000 hertz.d. 22,000 hertz.


31. A guitar player controls the notes produced by placing her fingers at specific positions on the strings. The notes are produced as a result of:a. diffraction.b. polarization.c. resonance.d. refraction.


32. Loud noises damage the ear because:a. they can block the ear canal.b. they are transmitted to the ear faster in the atmosphere than quiet noises.c. they can cause tiny hairs in the cochlea to break.d. their frequency exceeds 20,000 hertz.


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Chapter 21: Sound—Multi-format Bank

MODIFIED TRUE/FALSE

1. The frequency of a fire siren sounds high while the frequency of a bass drum sounds low. A term commonly used to describe how we hear these frequency differences is rhythm. _________________________

ANS: F, pitch DIF: basic REF: section 21.1

2. Sound waves are an example of transverse waves. _________________________

ANS: F, longitudinal DIF: basic REF: section 21.2

3. As the temperature of a gas increases the speed of sound increases. _________________________


4. A combination of sounds that is unpleasant or unsettling, generally caused by beats, is known as consonance. _________________________

ANS: F, dissonance DIF: basic REF: section 21.3

5. The perception of sound starts with the cochlea. _________________________

ANS: F, eardrum DIF: basic REF: section 21.3

COMPLETION

1. A unit used to measure the loudness of sound is the ____________________.

ANS: decibeldB


2. Performers often impersonate the voice of famous personalities. However, even the best performer’s voice can be distinguished from the famous personality because each voice consists of characteristic ____________________.

ANS: harmonicsfrequencies


3. Some jet planes fly faster than the speed of sound. The term used to describe their motion is ____________________.

ANS: supersonic DIF: basic REF: section 21.1

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4. Sound of very high frequency, inaudible to the human ear but used by doctors to create images inside the body, is called ____________________.

ANS: ultrasound DIF: basic REF: section 21.2

5. Increasing the wavelength of a sound produced with constant frequency causes the speed of the sound to ____________________. (increase, decrease, remain the same)

ANS: increase DIF: intermediate REF: section 21.2

6. Increasing the frequency of a sound produced with constant speed causes the wavelength of the sound to ____________________. (increase, decrease, remain the same)

ANS: decrease DIF: intermediate REF: section 21.2

7. Two musical instruments produce a note at the same time.The notes are nearly the same frequency. A person listening hears a rapid oscillation of sound that alternates between loud and soft. This phenomenon is known as ____________________.

ANS: beats DIF: basic REF: section 21.3

SHORT ANSWER

1. List the speed of sound in each of the following media in order from fastest to slowest.a. Water at 20ºCb. Air at 20ºCc. Helium at 20ºCd. Steel at 20ºCe. Air at 0ºC

ANS: d. Steel at 20ºCa. Water at 20ºCc. Helium at 20ºCb. Air at 20ºCe. Air at 0ºC


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2. State three characteristics of sound that suggest to scientists that it is transmitted as a wave.

ANS: Answers may vary. Correct answers include any three of the following answers:1) It has frequency.2) It has a measurable wavelength.3) It has amplitude that we hear as loudness.4) Its speed may be calculated using the wave equation: speed = frequency × wavelength.5) Resonance occurs with sound.6) It can be reflected.7) It can be refracted.8) It can be absorbed.9) It may display diffraction and interference.


3. In a motion picture, an asteroid on collision-course with Earth is struck by a missile before reaching Earth’s atmosphere. The asteroid explodes with a loud noise. Explain why this is not an accurate representation.

ANS: Sound requires the oscillations of atoms to be transmitted and cannot travel in a vacuum. Since space is a vacuum beyond Earth’s atmosphere, there would be no noise associated with an exploding asteroid in space.


PROBLEM

1. What is the speed of a 17-meter long sound wave whose frequency is 20 hertz?

ANS:

Speed = 340 m/secspeed = frequency ×wavelength = 20 Hz× 17 m = 340 m/sec


To signal his friend who is 2,000 meters away, Terry taps on a steel railroad track. Putting her ear to the track, Renee hears the sound of the tapping 0.337 seconds after Terry taps the rail.

2. Calculate the speed of sound through the steel of the railroad track.

ANS: 5,935 m/sec

speed =distance

time=

2,000 m0.337 sec

= 5,935 m/sec


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3. Calculate the length of the wave in the steel track if the frequency of the tone Renee hears is 528 hertz.

ANS: wavelength = 11.2 meters

Using the speed of sound in steel calculated previously as 5,935 m/sec:

wavelength =speed

frequency=

5935 m/sec528 Hz

= 11.2 meters


4. Sound travels at a speed of 340 meters per second in air and at 960 meters per second in helium. If a guitar string vibrates in air at a frequency of 170 hertz, at what frequency would it vibrate in helium?

ANS: 480 hertzSince the string length is unchanged, the fundamental wavelength will be the same for both. Therefore, the ratio of velocity to frequency will be the same for both.vair

f air

=vhelium

f helium

340 m/sec170 Hz

=960 m/sec

f helium

f helium = 480 hertz


5. Tom can just see a salmon below his boat in the crystal-clear Adirondack waters of Lake George. He sends out a sound signal, SONAR, that travels at a speed of about 1,530 meters per second in water. After striking the salmon, the signal returns as an “echo” in 0.025 seconds. How much line should Tom reel out to dangle an enticing piece of bait in front of the salmon’s mouth?

ANS: Line length = 19.1 metersThe time for the sound signal to travel down and return (0.025 seconds) is twice the time to simply travel to the salmon. Therefore, it takes 0.0125 seconds for the signal to travel from the salmon to the boat.distance = speed × time = 1,530 m/sec × 0.0125 sec = 19.1 meters


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ESSAY

1. Describe how you hear the frequency of a fire truck siren change as the sound passes by you. What is this effect called?

ANS: As the fire truck approaches you, the frequency you hear increases. As the fire truck is right next to you, you hear the same frequency as someone on the fire truck hears. As the fire truck moves away from you, the frequency you hear decreases.

This is called the Doppler effect.


2. Explain how the speaker of a stereo system produces sound.

ANS: Anything that vibrates produces sound. A speaker vibrates at audible frequencies, first compressing air molecules and raising their pressure and then by reducing air pressure as it moves in the opposite direction. The back-and-forth motion of the speaker produces alternating layers of high and low pressure that travel away from the speaker as sound waves.


3. Compare the terms ultrasound and sonogram.

ANS: Ultrasound is any sound produced at frequencies exceeding the range of human hearing. Because it can penetrate materials such as human tissue, it can be used to produce an image of a beating heart or a baby while still in the mother’s body. It may used to analyze materials for structural integrity. In addition, it may be used to treat joint ailments with deep-heat therapy.

A sonogram is a special kind of graph that records sound as a picture that can show how loud a sound is at various frequencies. In this way, it may be used as a voice “fingerprint” to distinguish one person’s voice from another. A sonogram is also the name given to the picture produced by ultrasound analysis. In this case, it may also be called an ultrasonogram.

DIF: advanced REF: section 21.2, section 21.3

4. Why do musicians wear earplugs when playing in concerts?

ANS: The ear is sensitive to damage by loud noises. The chances that damage will occur increases with the length of exposure. Since musicians are exposed to loud music for extended periods of time, they wear earplugs to reduce the volume of the music and decrease the risk of damage.


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5. What is the range of frequencies to which the average human ear is sensitive? How does this change with age?

ANS: Normally, the human ear is sensitive to frequencies from 20 hertz to 20,000 hertz. As people age, their ability to hear higher frequencies decreases. While most children can detect frequencies near 20,000 hertz, for the average adult, the upper range of frequencies is about 15,000 hertz.


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Chapter 22: Light and Color—Multiple Choice Bank

MULTIPLE CHOICE

1. All of the following are characteristics of light EXCEPT that light:a. has color.b. has mass.c. can travel 7.5 times around the Earth in one second.d. travels in straight lines.


2. The process of making light with heat is called:a. photoluminescence.b. photosynthesis.c. incandescence.d. refraction.


3. The speed of light is ____ m/sec.a. 300b. 30,000c. 300,000d. 300,000,000


4. The use of fluorescent lights is more economical than incandescent bulbs because fluorescent bulbs:a. produce more heat than light.b. emit four times more light from the same amount of electricity.c. emit light from a hot, wire filament.d. can be used for hatching baby chicks as well as for lighting.


5. The speed of light is such an important speed it is represented by its own “symbol.” The symbol used to represent the speed of light is:a. Lb. vc. cd. @


6. Light travels in straight lines in a medium. Physicists call imaginary lines used to represent light in optical diagrams:a. light beams.b. sunbeams.c. light rays.d. spectral lines.


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7. If light bounces off the surface of a material, the change in direction is called:a. refraction.b. reflection.c. diffusion.d. interference.


8. Light shining through a bottle of water is often bent. This change in direction is called:a. refraction.b. reflection.c. diffusion.d. interference.


9. Of the objects listed, the one that you do NOT see because of reflected light is:a. a painting.b. the moon.c. the sun.d. the wall of your home.


10. A straw will appear broken in a glass of water because light traveling from air to water is:a. reflected.b. refracted.c. diffused.d. diffracted.


11. Which of the following colors of light has the highest energy?a. Redb. Yellowc. Blued. Violet


12. During an electrical storm, thunder associated with a distant lightning strike is heard:a. after the lightning is seen because sound travels slower than light.b. at the same time as the lightning because they occur at the same time.c. before the lightning is seen because sound travels faster than light.d. at the same time as the lightning because they travel at the same speed.


13. Most of the objects that we see are visible to us because they ____ light.a. refractb. diffractc. reflectd. emit


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14. When a light beam travels from a light source to your eyes, we know it:a. travels in straight lines.b. follows a zigzag path.c. moves very slowly.d. slows down and speeds up.


15. Sound travels 0.2 miles in one second. Lightning is seen to strike in the distance. Thunder associated with the strike is heard 10 seconds later. The lightning occurred at a distance of ____ mile(s).a. 10b. 5c. 2d. 0.2


16. If the distance between a small light source and a screen is doubled, the intensity of light on the screen ____ by ____ times.a. increases, twob. decreases, twoc. increases, fourd. decreases, four


17. If the sun, which is located approximately 1.49 × 1011 meters from Earth, were to suddenly stop emitting light, how much time would pass before people on Earth saw no sunlight?a. 1.49 × 1011 secondsb. 0 secondsc. 4.96 × 102 secondsd. 400 minutes


18. Photoreceptors commonly called cone cells respond to:a. red, blue, and green.b. yellow, cyan, and magenta.c. black, white, and gray.d. yellow, cyan, magenta, and black.


19. Rod cells respond to:a. white, black, and gray.b. red, white, and blue.c. red, green, and blue.d. red, yellow, and blue.


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20. The additive primary colors are:a. red, white, and blue.b. cyan, magenta, and yellow.c. red, yellow, and blue.d. red, green, and blue.


21. The color of a light source is related to its:a. speed.b. energy.c. amplitude.d. frequency multiplied by its wavelength.


22. When cone cells are stimulated by equal amounts of red, green, and blue light, we see:a. no light.b. white light.c. red light because it is the dominant color.d. orange light.


23. The portion of the electromagnetic spectrum most useful to living things is:a. microwave radiation.b. infrared radiation.c. ultraviolet radiation.d. visible light.


24. Color blindness is a condition that affects:a. the retina.b. rod cells.c. cone cells.d. the optic nerve.


25. Color televisions produce images by mixing dots of:a. red, white, and blue.b. red, yellow, and blue.c. red, green, and blue.d. magenta, yellow, and cyan.


26. The subtractive primary colors are:a. red, white, and blue.b. cyan, magenta, and yellow.c. red, yellow, and blue.d. red, green, and blue.


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27. An object that appears red in sunlight is illuminated only by blue light. It will appear to be:a. black.b. white.c. red.d. violet.


28. When white light illuminates a green leaf, ____ are the two colors of light that are mainly absorbed.a. green and yellowb. green and redc. red and blued. blue and yellow


29. The color of light that is LEAST useful for the growth of green plants is:a. red.b. green.c. blue.d. white.


30. Our vision is based on:a. the CMYK color process.b. the additive color process.c. the subtractive color process.d. constructive interference.


31. Compared to the best video equipment available, the human eye can detect ____ from light.a. a little more informationb. the same amount of informationc. much more informationd. much less information


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Chapter 22: Light and Color—Multi-format Bank

MODIFIED TRUE/FALSE

1. We see most objects around us because they refract light. _________________________

ANS: F, reflect DIF: basic REF: section 22.1

2. As light bounces off a surface, it is described as being refracted. _________________________

ANS: F, reflected DIF: basic REF: section 22.1

3. The letter used to represent the speed of light is L. _________________________

ANS: F, c DIF: basic REF: section 22.1

4. Photoreceptors sensitive to colored light are called rod cells. _________________________

ANS: F, cone DIF: basic REF: section 22.2

5. The additive primary colors are red, yellow, and blue. _________________________

ANS: F, red, green, and blue DIF: basic REF: section 22.2

6. An object that appears red in sunlight is illuminated by green light.The color of the object appears green. _________________________

ANS: F, black DIF: intermediate REF: section 22.3

COMPLETION

1. The amount of light energy falling on a surface per second is a measure of the light ____________________.

ANS: intensity DIF: basic REF: section 22.1

2. The speed of light is ____________________ meters per second.

ANS: 3 × 108

300,000,000


3. The color of visible light with the lowest energy is ____________________.

ANS: red DIF: basic REF: section 22.2

4. Human color vision is due to the ____________________ color process.

ANS: additive DIF: intermediate REF: section 22.2

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5. The color mixing process using the CMYK color process is called the ____________________ color process.

ANS: subtractive DIF: basic REF: section 22.3

6. The cover on a book appears blue in white light because it ____________________ blue light and ____________________ the other colors of light.

ANS: reflects, absorbsreflects, subtracts


SHORT ANSWER

1. List three characteristics of light.

ANS: Answers may vary. Correct answers include any three of the following:It travels in straight lines.It has color.It can be bent (refracted or diffracted) or reflected.It has intensity (brightness).It travels at the highest possible speed.It has a frequency and wavelength.


2. Light intensity is the amount light energy falling on a surface every second. Name a metric unit that could be used to measure light intensity.

ANS: joules/sec/m2 or watts/m2


3. Another name for the subtractive color process is the CMYK color process. What do the letters CMYK represent?

ANS: C = cyanM = magentaY = yellowK = black


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4. Indicate the color the apple appears for each of the following lights:a. A pure red apple illuminated by white light.b. A pure red apple illuminated by red light.c. A pure red apple illuminated by blue light.

ANS: a. redb. redc. black


PROBLEM

1. The speed of light (3 × 108 m/sec) was determined by allowing light to travel 40 kilometers (40,000 m) and measuring the time for it to travel that distance. How much time was required for light to travel that distance?

ANS: speed of light = 3× 108 m/sec

time = distance ÷ speed = 40,000 mÊËÁÁ

ˆ¯ ÷ 3 × 108 m/secÊ

ËÁÁÁ

ˆ¯˜ = 1.3 × 10-4 seconds


2. A light year is the distance light travels in one year. What is this distance in meters?

ANS:

one year = 365 days ×24 hrsday

×60 min

hrs×

60 secmin

= 3.16 × 107 sec

speed of light = 3 × 108 m/sec

distance = velocity× time = 3 × 108 m/secÊËÁÁÁ

ˆ¯˜ × 3.16 × 107 secÊ

ËÁÁÁ

ˆ¯˜ = 9.5 × 1015 meters


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3. A small light source located 2 meters from a wall illuminates the wall with an intensity of 800 watts per square meter. Calculate the intensity of light illuminating the wall if the light source is moved to a distance of 6 meters from the wall.

ANS: intensitya × distance

a

2 = intensityb × distanceb2

800 W/m2ÊËÁÁÁ

ˆ¯˜ × 2 m( ) 2 = intensityb × 6 m( ) 2

intensityb =800 W/m2Ê

ËÁÁÁ

ˆ¯˜ × 2 m( ) 2

6 m( ) 2 = 88.9 W/m2


ESSAY

1. The starter at a track meet shoots a blank pistol to start a 100-meter race. The timers at the other end of the track are told to start their watches when they see the smoke from the pistol, not when they hear the discharge. Explain why they should be given this instruction.

ANS: The gun produces the sound and the smoke at the same time. Since light (3 × 108 m/sec) travels faster than sound (340 m/sec), the timers at the other end of the track see the smoke before they hear the sound but at the same time as runners hear the gun. Timers start their watches when runners hear the gun instead of 0.29 seconds later when they would hear the gun.


2. Why are fluorescent lights considered more efficient than incandescent lights?

ANS: Fluorescent lights produce light using most of the input energy to raise the energy level of the electrons for light production, wasting very little of the energy on heating the atoms. Incandescent lights, on the other hand, convert most of the input energy to heat and only a small portion to light.


3. Describe the basic difference between the operation of a video camera and a television.

ANS: A television makes different colors by lighting the red, green, and blue pixels in the screen to different percentages. A video camera does the opposite. A video camera has red, green, and blue sensors similar to the cones in your eyes. The camera records images by measuring the percentages of red, green, and blue in the light coming through the camera lens.


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4. Explain the difference between the image of a yellow banana on a computer screen and an image of the banana on a piece of paper.

ANS: Objects that produce light (such as a computer screen) create colors by the additive process. To produce the yellow banana image on a computer screen, small dots of red and green light are combined to produce yellow light by addition. To produce the same color on paper, the CMYK process, a subtractive process is used. For the banana, yellow pigment would probably be used.


5. A computer monitor screen is capable of producing millions of colors. Explain how that may be done using only three colors: red, blue, and green.

ANS: Devices that produce light create colors according to the RGB model using the additive process. Using various combinations of the three colors, all colors of the spectrum can be produced. By varying the intensity (brightness) of each color in levels from 0 to 255, combinations of the primary additive colors can produce 2563, or nearly 17 million, different colors.


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Chapter 23: Optics—Multiple Choice Bank

MULTIPLE CHOICE

1. A glass window is best described as a(n) ____ material.a. transparentb. translucentc. absorbingd. reflecting


2. Wax paper is best described as a(n) ____ material.a. transparentb. translucentc. absorbingd. reflecting


3. A black asphalt road is best described as a(n) ____ material.a. transparentb. translucentc. absorbingd. reflecting


4. A converging lens ALWAYS:a. causes light rays come together.b. makes objects viewed through them appear smaller.c. causes light rays to spread apart.d. distorts light by reflecting it in different directions.


5. The light ray which strikes the surface of an optical device is known as the ____ ray.a. incidentb. reflectedc. refractedd. diffuse


6. The type of reflection in which the light is scattered into many directions is known as:a. specular.b. diffuse.c. refracted.d. regular.


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7. All of the following statements about perfectly polished surfaces are true EXCEPT:a. the surface itself seems invisible.b. the surface creates diffuse reflection.c. all parallel light rays from a source are reflected parallel by the surface.d. the surface creates specular reflection.


8. Simple optical devices include lenses, mirrors, and:a. pencils.b. pens.c. prisms.d. crayons.


9. Referring to the diagram, which angle represents the angle of reflection?

a. 1b. 2c. 3d. 4


10. The line drawn on a ray diagram perpendicular to the surface at the point where the incoming light strikes the surface is called the:a. ray.b. normal line.c. incident light.d. reflected light.


11. All of the following statements correctly describe light rays EXCEPT that light rays:a. can be seen coming from a light by squinting your eyes.b. can be used to predict the size and location of an image.c. are often represented with arrows on ray diagrams.d. are imaginary lines which represent a thin beam of light.


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12. You can clearly see yourself in a flat (plane) mirror because of which kind of reflection?a. Realb. Specularc. Diffused. Refracted


13. The diagram below represents a light ray striking a flat mirror:

What is the value in degrees for the angle of incidence?a. 20ºb. 35ºc. 55ºd. 70º


14. According to the law of reflection, the angle of incidence is always:a. bigger than the angle of reflection.b. equal to the angle of reflection.c. smaller than the angle of reflection.d. determined by measuring between the incident and reflected rays.


15. You are holding a paper with the word PHYSICS printed on it in front of a flat mirror. All of the following statements about the image formed by the mirror are correct EXCEPT that the:a. image appears twice as far from you as you are from the mirror.b. image is the same size as you.c. word PHYSICS is written backward in the mirror.d. word PHYSICS is written upside down in the mirror.


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16. An object is placed in front of a mirror as shown in the diagram below:

Which diagram represents the image of that object in the mirror?

a. c.

b. d.


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17. A tall person’s eye level is at 2.0 meters high and his feet are at 0 meters high:

If light rays are reflected so that he is able to see an image of his feet, approximately how far from the floor do these rays strike the mirror?a. 2.0 mb. 1.0 mc. 0.25 md. 0 m

ANS: BTo see his feet, the incident ray of light from his feet must strike the mirror and then the reflected ray must reach his eyes. Since the law of reflection states that the angle of incidence must equal the angle of reflection, the incident ray must strike the mirror halfway between his feet at 0 meters and his eyes at 2 meters, or it strikes the mirror at 1.0 meters from the floor.


18. The bending of a light ray as it travels from air into water is known as:a. specularization.b. reflection.c. refraction.d. diffusion.


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19.

When light passes, as shown in the illustration above, from a material with a smaller index of refraction into a material with a higher index of refraction it will:a. travel straight through with no bending.b. be bent toward the normal.c. be bent away from the normal.d. travel down the normal.


20.

The diagram best illustrates:a. scattering and diffraction.b. reflection and interference.c. transmission and Doppler effect.d. refraction and dispersion.


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21.

The diagram shows a beam of light passing through a curved glass fiber. This is possible due to the effect of:a. dispersion.b. total internal reflection.c. polarization.d. diffraction.


22. The color of light that is refracted most when it passes through a prism is:a. red.b. orange.c. green.d. blue.


23. Which diagram correctly illustrates light rays as they pass through a converging lens?

a. c.

b. d.


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24. The color of light for which the index of refraction is greatest is:a. blue.b. green.c. yellow.d. red.


Material Index of RefractionVacuum 1.0Air 1.0001Water 1.33Ice 1.31Glass 1.5Diamond 2.42

Table 23-1A

25. Referring to Table 23-1A, as light travels from a vacuum into a substance, in which substance will the light experience the greatest change of direction?a. Air b. Waterc. Glassd. Diamond


26.

The diagram above shows a ray of light (R) incident upon a surface at an angle which is greater than the critical angle. Through which point is the ray most likely to pass? Refer to Table 23-1A.a. Ab. Bc. Cd. D


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27. The illustration shows the image of four fish in a pond:

If a fish is actually located at position B, at which position would the IMAGE of that fish appear for a person looking into the pond while standing on the side of the pond? Refer to Table 23-1A.a. Ab. Bc. Cd. D

ANS: AThe light rays from the fish will be bent as they pass from the water to the air, making it appear that the fish is higher in the water than it really is.


28. A light ray passes from air into a glass block. Referring to Table 23-1A, through which point is the ray most likely to pass?

a. Ab. Bc. Cd. D


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29. The diagram below represents a ray of green light passing through a glass prism (n =1.61).

If the same light were to pass through a prism made of diamond (n = 2.42), the path of the light would be best represented by:

a. c.

b. d.


30. A light ray passes through a converging lens, but does not bend. Describe its path.a. Above the optical axisb. Below the optical axisc. Along the optical axisd. Crossing the optical axis


31. When photographic film is exposed to light, the image produced on film is called a:a. positive.b. negative.c. CCD.d. pixel.


32. Lenses that are thicker around the edges of the lens than in the middle are:a. convex.b. converging.c. diverging.d. dividing.


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33. All of the following statements about images are correct EXCEPT that images:a. are organized light.b. can be touched like any object..c. can be formed by lenses.d. form where light rays converge.


34. The type of image that can be projected on a screen is always:a. virtual.b. real.c. enlarged.d. smaller.


35. A lens is used to produce an image of an object. If the object is 4 centimeters tall and the image is 12 centimeters high, the magnification of that lens is:a. 48x.b. 16x.c. 8x.d. 3x.


36. A virtual image of an object will be produced by a converging lens if the object is placed:a. more than five focal lengths from the lens.b. precisely two focal lengths from the lens.c. just beyond one focal length from the lens.d. closer to the lens than one focal length.


37. In the diagram below, f represents the focal point and 2f represents a point at twice the focal length from the lens.

In which direction does most of the light in Ray R pass?a. Ab. Bc. Cd. D


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In each ray diagram, f represents the focal point of the lens and 2f represents a point at twice the focal length from the lens.

A. B.

C. D.

Figure 23-1

38. Which ray diagram in Figure 23-1 best represents the formation of a real, enlarged image of the object?a. Ab. Bc. Cd. D


39. Which ray diagram in Figure 23-1 best represents the formation of a virtual, reduced image of the object?a. Ab. Bc. Cd. D


40. The image produced by a diverging lens is always:a. smaller and upside down.b. larger and upside down.c. smaller and right-side-up.d. larger and right-side-up.


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41. How many numbers must be stored in order to record a 3 megapixel colored image on a CCD?a. 256b. 788c. 3 milliond. 9 million


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Chapter 23: Optics—Multiple-format Bank

MODIFIED TRUE/FALSE

1. An optical instrument that forms images by reflecting light is called a lens. _________________________

ANS: F, mirror DIF: basic REF: section 23.1

2. An imaginary line drawn perpendicular to the surface of an optical device where a light ray strikes the surface is called the optical axis. _________________________

ANS: F, normal line DIF: basic REF: section 23.1

3. Light reflected from a highly polished surface represents specular reflection. _________________________


4. When white light is directed at a triangular prism, the colors of the light are separated according to their index of refraction. This phenomenon is known as diffusion. _________________________

ANS: F, dispersion DIF: basic REF: section 23.2

5. A lens that is thicker on the edges and thinner in the middle will cause light rays to converge. _________________________

ANS: F, diverge DIF: intermediate REF: section 23.3

COMPLETION

1. An accurately drawn sketch showing how light rays interact with lenses, mirrors, and other optical devices to form an image is called a ____________________ (two words).

ANS: ray diagram DIF: basic REF: section 23.1

2. An imaginary line that represents a thin beam of light is called a light ____________________.

ANS: ray DIF: basic REF: section 23.1

3. The study of how light behaves is called ____________________.

ANS: optics DIF: basic REF: section 23.1

4. A number that represents the ability of a material to bend light is called the index of ____________________.

ANS: refraction DIF: basic REF: section 23.2

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5. Light rays that enter a converging lens parallel to its axis bend to meet at a point called the ____________________ point.

ANS: focal DIF: basic REF: section 23.3

6. The type of image formed when light rays do not actually come together to form the image is known as ____________________.

ANS: virtual DIF: intermediate REF: section 23.3

SHORT ANSWER

1. State the law of reflection.

ANS: The angle of incidence of any light ray equals the angle of reflection for that ray.


2. Prisms are triangular blocks of glass with flat, polished surfaces that cause light to change direction. Name three optical devices in which prisms are used.

ANS: Answers will vary. Correct answers include:telescopes, supermarket scanners, binoculars, cameras


3. Classify each of the following materials as being mostly transparent, translucent, absorbing, or reflecting.

1) a black t-shirt2) tissue paper3) a shiny stainless steel spoon4) clear plastic wrap5) wax paper6) black velvet curtains

ANS: 1) absorbing2) translucent3) reflecting4) transparent5) translucent6) absorbing


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4. Material Index of RefractionVacuum 1.0Air 1.0001Water 1.33Ice 1.31Glass 1.5Diamond 2.42

The diagrams represent light traveling from water (A) into another material (B). Using the chart above, label material B for each diagram as air, water, glass or diamond.

ANS: a. water b. glass c. air d. diamond


5. Examine the ray diagram of the lens. Identify each part of the diagram, A-D.

ANS: A. The focal lengthB. The lensC. The focal points of the lensD. The optical axis of the lens


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6. Describe how you can determine whether an image is real or virtual.

ANS: Real images can be projected on a screen; virtual images cannot.

Real images produced by a single lens are formed upside down; virtual images are right-side-up.


PROBLEM

1. Using a protractor and straight edge, complete the ray diagram below by drawing the normal and the reflected ray.

ANS:


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2. The diagram represents an object positioned in front of a plane mirror. Complete the drawing by showing the position of the virtual image that would be formed.

ANS: The image should be shown as right-left reversed. Furthermore, it should be positioned as far behind the mirror surface as the object is in front.


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3. Use a protractor to determine the size of the angle of incidence for the light ray represented by the diagram below.

ANS: 40º ± 1ºNote: The angle of incidence is measured from the incident ray to the normal line.


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4. A diver points a flashlight at the surface of a swimming pool at the critical angle as shown in the diagram. Show the path the refracted ray would take by completing the diagram.

ANS:

The diagram should show the beam of the flashlight as parallel to the surface of the water at the surface.


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5. An object is pictured at a distance of 2 focal lengths from a lens. Draw a ray diagram showing the formation of the image.

ANS:

The diagram may show the intersection of any combination of 2 of any of the following 3 light rays drawn to produce an image:1. A light ray drawn from a point on the object through the optical center of the lens.2. A light ray drawn through the focal point, extended parallel to the optical axis on the opposite side of the lens.3. A light ray drawn parallel to the optical axis, extended through the focal point on the opposite side of the lens.


ESSAY

1. Overlapping rays of red, green, and blue light are directed at a triangular prism in a direction causing the dispersion of the light, which then falls on a screen. Define dispersion and explain the basis for this phenomenon. Describe what an observer might see.

ANS: Dispersion refers to the separation of the colors of light based upon the index of refraction for each color of light. Since the index of refraction for red is lowest, it is bent (refracted) the least. The prism would bend blue the most because it has the highest index of the colors used. An observer might see a spectrum of colors of red, green, and blue projected on a screen with red on top and blue on the bottom with green in the middle.


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2. Why do we tend to use cameras with lenses versus the less expensive pinhole camera? Answer this question in terms of a lens vs. a pinhole.

ANS: Brighter images can be produced if an optical system collects more light. Lenses gather much more light than tiny pinholes. The images produced are much brighter.


3. Why are multiple lenses used in optical systems?

ANS: Multiple lens systems are used for convenience in changing the size of the image.The size of the image produced by a single lens depends on the distance between the lens and the object. Instead of changing the distance between a faraway object and the lens, multiple lens systems can produce images of varying sizes by changing the position of the lenses relative to one another.


4. Describe the differences between images formed by a converging lens and a diverging lens.

ANS: Diverging lenses always produce images that are smaller than the object and right-side-up. The image from a diverging lens cannot be projected on a screen; it is virtual.

The images produced by a converging lens vary depending on the distance of the object from the lens. When the object is beyond the focal length of the lens, the image is real and upside-down. The image increases in size from smaller than the object to larger than the object as the object is moved closer to the focal point. The image is the same size as the object when the object is at two times the focal length. When the object is inside the focal length the image is magnified, virtual, and right-side-up. In theory, if the object is at the focal point, no image is formed.


5. You learned that real images can be projected on a screen and are always formed upside down. The images seen by your eyes and the images from a movie are both real images that are projected on a “screen” (in the case of your eye, the image is projected onto the retina). Explain why the images formed on your retina and on a movie screen are seen right-side-up even though they are real images.

ANS: We see images as right-side up because our brain is able to invert the image to match the feedback our other senses are sending to the brain. Movies appear right-side up because the film is set up in the projector upside down.


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Chapter 24: The Physical Nature of Light—Multiple Choice Bank

MULTIPLE CHOICE

1. The electromagnetic waves with the shortest wavelength are:a. microwaves.b. gamma rays.c. radio waves.d. visible light waves.


2. The electromagnetic waves that are beneficial in small amounts but responsible for skin cancer, sunburn, and cataracts in larger amounts are ____ waves.a. visible lightb. AM radioc. ultravioletd. infrared


3. The energy of light is directly related to its:a. amplitude.b. brightness.c. speed.d. frequency.


4. The speed of light is special because it:a. can be slowed down in a vacuum.b. is the greatest speed attainable in nature.c. is similar to the speed of sound.d. is easily measured using stopwatches.


5. Which statement about the frequency and wavelength of visible light is CORRECT?a. The frequencies and wavelengths of light are measured using the same units.b. The frequencies and wavelengths of light are similar to the frequencies and wavelengths

of sand.c. The frequencies of light are incredibly high and the wavelengths of light are tiny.d. The frequencies of light are low and the wavelengths of light are large.


6. To calculate the speed of light in a material:a. divide the speed of light in a vacuum by the index of refraction for the material.b. multiply the speed of light in a vacuum by the index of refraction for the material.c. divide the index of refraction for the material by the speed of light in a vacuum.d. add the speed of light in a vacuum to the index of refraction for the material.


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7. Compared to the speed of light in a vacuum, the speed of light traveling in a material like glass:a. is slower.b. is unchanged.c. is faster.d. may be faster or slower depending upon the material.


8. All electromagnetic waves have the same speed in:a. water.b. glass.c. a vacuum.d. plastic.


9. A gamma ray with a frequency of 6.0 × 1020 hertz has a wavelength of ____ meters.a. 1.7 × 10-21

b. 5.0 × 10-13

c. 2.0 × 1012

d. 6.0 × 1020


10. All of the following waves travel at 3 × 108 meters per second EXCEPT:a. light waves.b. sound waves.c. microwaves.d. X rays.


11. Which of the following can NEVER happen when light travels from one material into another?a. The wavelength decreases.b. The frequency decreases.c. The speed increases.d. The speed decreases.


12. The speed of light in a vacuum is 3 × 108 meters per second. The speed of light in a diamond whose index of refraction is 2.42 is ____ m/sec.a. 7.26b. 7.26 × 108

c. 1.24d. 1.24 × 108


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13. Light waves display all of the following characteristics EXCEPT:a. resonance.b. diffraction.c. mass.d. wavelength.


14. The addition of waves that creates a pattern of alternating dark and light bands is called:a. diffusion.b. refraction.c. interference.d. reflection.


15. The diagram below represents sunglasses being used to eliminate glare:

The phenomenon represented in the diagram is:a. dispersion.b. polarization.c. refraction.d. reflection.


16. A device that measures the wavelength of light is called a:a. polarizer.b. spectrometer.c. liquid crystal diode.d. magnetron.


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17. The diagram below illustrates two sources of light energy produced at a constant frequency such that the light falling on the screen at points A and C is bright.

There is no light at point B. The wave phenomenon represented by this diagram is:a. interference.b. polarization.c. reflection.d. refraction.


18. A device whose operation depends upon the ability of light waves to be polarized is the:a. LCD.b. magnetron.c. magnet.d. spectrometer.


19. A material that selectively absorbs light depending on the orientation of its electromagnetic waves acts as a:a. magnetron.b. polarizer.c. diffraction grating.d. spectrometer.


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20. Two wave sources operating in phase in the same material produce circular wave patterns shown in the diagram below. The solid lines represent wave crests and the dashed lines represent wave troughs.

The greatest destructive interference occurs at point:a. Ab. Bc. Cd. D


21. The diagram below represents waves of wavelength λ passing through two small openings, A and B, in a barrier. The solid lines represent wave crests and the dashed lines represent wave troughs.

Compared to the distance from B to P, the distance from A to P is:a. 1λ longer.b. 2λ longer.c.

1

2λ longer.

d. the same.


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22. Looking through a spectrometer, you see a line of light at 410 nanometers. This means the wavelength of the light is 410 nanometers. The color of this light is:a. red.b. yellow.c. green.d. violet.


23. Phosphorus atoms embedded in plastic that absorb light energy will slowly release the energy in a glow-in-the-dark process known as:a. photosynthesis.b. phototropism.c. photoluminescence.d. polarization.


24. Light is composed of tiny particles of energy known as:a. protons.b. neutrons.c. electrons.d. photons.


25. As atoms gain energy due to a temperature increase, the color of the light emitted by the atoms may change from:a. blue to green.b. red to yellow.c. green to orange.d. violet to red.


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Chapter 24: The Physical Nature of Light—Multi-format Bank

MODIFIED TRUE/FALSE

1. The electromagnetic spectrum includes visible light, ultraviolet light, and radio waves. _________________________


2. The energy of waves is proportional to the speed of a wave. _______________________

ANS: F, frequency DIF: basic REF: section 24.1

3. Light can be described in terms of particles of energy called protons. _______________________

ANS: F, photons DIF: basic REF: section 24.3

4. The process of releasing stored energy as light is called photoluminescence. _______________________


5. The nucleus of an atom responsible is(are) for absorbing and re-emitting energy as light. _______________________

ANS: F, electrons DIF: basic REF: section 24.3

COMPLETION

1. When light crosses a boundary between materials of different optical densities, it changes speed and ____________________.

ANS: wavelength DIF: intermediate REF: section 24.1

2. Electromagnetic waves may be polarized because they are ____________________ waves.

ANS: transverse DIF: basic REF: section 24.2

3. A series of parallel grooves on a piece of plastic or glass that can be used to create an interference pattern is called a _________________________. (two words)

ANS: diffraction grating DIF: basic REF: section 24.2

4. A device that measures the wavelength of light using a diffraction grating is called a ____________________.

ANS: spectrometer. DIF: basic REF: section 24.2

5. Light waves that have one direction of vibration may be described as being ____________________.

ANS: polarized DIF: basic REF: section 24.2

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SHORT ANSWER

1. Why is the speed of light in a vacuum considered to be a special speed?

ANS: Nothing in the universe is capable of traveling faster than light in a vacuum. (This fact forms the cornerstone of Albert Einstein’s theory of relativity, a theory relating space and time.)


2. As light passes from a vacuum into a material, how are the speed, frequency, and wavelength affected?

ANS: The speed decreases, the frequency remains the same, and the wavelength decreases.


3. State the relationship between the frequency of a light source and its energy.

ANS: As the frequency of a light source increases, its energy increases. Energy and frequency are directly proportional.


4. How are electromagnetic waves created?

ANS: Electromagnetic waves are created by the oscillation of magnetic or electric fields.


5. When the wavelength and frequency for each of the colors (listed in the table below) is multiplied, each product yields approximately the same answer. What is the significance of this “coincidence”? In what units does the answer appear?

Color Wavelength (nanometers) Frequency (Thz)Red 650 462

Orange 600 500Yellow 580 517Green 530 566Blue 470 638

Violet 400 750

ANS: The product of wavelength times frequency is equal to the speed of a wave. The speed of light in a vacuum is the same for all colors of light, 3 × 108 m/sec or 3 × 105 km/sec. It is given in units of kilometers per second in this case.


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6. Explain the importance of Thomas Young’s experiments that produced interference patterns.

ANS: Thomas Young’s experiment provided the most convincing evidence in support of the wave nature of light.


PROBLEM

1. Light travels through the transparent material lucite at a speed of 2.0 × 108 meters per second. What is the index of refraction for lucite?

ANS:

n =speed of light in a vacuumspeed of light in a material

=3× 108 m/sec2× 108 m/sec

= 1.5


2. The wavelength of a certain frequency of green light is 5.30 × 10-7 meters. What is the frequency of this green light?

ANS: v = f × λ

f =vλ=

3 × 108 m/sec5.30 × 10−7 m

= 5.66× 1014 hertz


3. The light from Samantha’s flashlight travels in air at a speed of about 3.0 × 108 m/sec. The index of refraction for water is 1.33. If she shines the flashlight into her family’s swimming pool, what is the speed of the light in the water?

ANS:

n =speed of light in a vacuumspeed of light in a material

speed of light in water =speed of light in a vacuum

n=

3× 108 m/sec1.33

= 2.26 × 108 m/sec


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ESSAY

1. What experimental proof is there to support the theory that light is a wave?

ANS: Light shows interference, diffraction, resonance, frequency, wavelength, and it has the same relationship between speed, frequency, and wavelength as other waves. Thomas Young’s experiment with the diffraction grating in 1807 demonstrated that light is a wave.


2. Describe the appearance of an interference pattern. Explain how an interference pattern is created.

ANS: An interference pattern is a pattern of alternating bight and dark bands of light created by a diffraction grating. It is created by the addition of two waves. At the bright bands, the waves interfere constructively; at the dark bands, the waves interfere destructively.


3. Explain how glow-in-the-dark plastic provides evidence to verify the theory that photon emission is caused by the interaction between a single electron and a single photon.

ANS: Photoluminescent plastic generally emits pale green light. If a red light is used to illuminate the plastic, no light is given off no matter how intense the red light. If the electrons could absorb two or more photons, a number of “red” photons should give an electron enough energy to excite the electron to emit a photon. This has not been observed. However, if a blue light of even low intensity is directed toward the plastic, green light is emitted. This indicates that even one photon hitting the plastic causes emission of green light.


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