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Apr 10­9:31 PM

9.5 Relating Speed to Distance and Time

Apr 10­9:31 PM

Speed­

• Formula for speed (or velocity):V = d (distance)

t (time)http://www.youtube.com/watch?v=9s9td5kvK5c

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Apr 10­9:46 PM

3 Types of Speed

Apr 10­9:36 PM

1. Average speed ­the total distance divided by the total time ­ this would include changes of speed and stops. The defining formula for average speed is : v av = ∆ d ∆ t The change in a measurement is signified by using the Greek letter ‘delta’ ∆ .

• Think starting and stopping (bathroom breaks)

http://www.youtube.com/watch?v=y40aVo90ETE

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Apr 10­9:38 PM

2. Instantaneous speed­ the speed measured at a moment in time

• Think radar gun

http://www.youtube.com/watch?v=5IOeOnKPynw

Apr 10­9:43 PM

3. Constant speed­ a condition which exists when the same instantaneous speed is measured over a specific time frame.

For example:If over a 5 minute period the speed was checked 3 times and each time the speed was the same, one could say that this object had constant speed

• Think cruise control

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Apr 10­10:38 PM

Homework: #7­10, pg 358­9

Apr 16­9:30 AM

7. a) The Breitling Orbiter travelled 40 814 km in 19 d, 21 h, and47 min. What was its average speed?

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Apr 16­9:35 AM

7. b) Using the average speed from (a), how long would it take to cross a distance of 6670 km?

Apr 16­9:36 AM

7. c) How far did the balloon travel on the final leg, 18 h at anaverage speed of 210 km/h?

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Apr 16­9:37 AM

8. a) The Thrust SCC jet car travelled 604 m at an average speed of 341 m/s. How long did this take?

Apr 16­9:40 AM

8. b) Convert 341 m/s to km/h.

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Apr 16­9:43 AM

9. In a marathon race, one runner moving at 5.0 m/s passes anotherrunner moving at 4.5 m/s. What is the distance betweenthe two runners 10 min later?

Apr 16­9:45 AM

10. a) The hand of the Canadarm can move up to 60 cm/s without aload attached. What is the minimum time for the arm to move 1.20 m?

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Apr 16­9:46 AM

10. b) When moving an object, the speed is slightly less than60 cm/s. With a load attached, will the time be more or less than your answer from (a)to move the same 1.20 m distance?

Explain your answer!

Apr 16­9:49 AM

10. c) The Canadarm takes 30 s to move equipment from the cargo bay. In this time, the shuttle moves 232 km throughspace. What is the speed of the shuttle in km/s?

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Apr 16­9:50 AM

10. c) What is the shuttle's speed in km/h?

*How many seconds are there in one hour?

Apr 16­9:51 AM

Formal Lab Report

What % of cars speed through the Victoria Street school zone?

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Apr 16­9:53 AM

Working with a partner, you will design and carry out an experiment to determine the % of speeders in an area near Kensington Intermediate High School.

We will develop an objective for the experimentas a whole class group, and each pair will agreeon their own hypothesis.

Apr 16­9:55 AM

You will then have to take into account and try to eliminate variables affecting the experiment, and come up with a procedure to test your hypothesis.

Things to keep in mind:

Safety; materials required; accuracy and precision of your measurements; how your data will be recorded; how you will calculate an answer to your hypothesis; possible sources of error, and how to minimize them.

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Apr 16­10:00 AM

Objective:

Take a few minutes to discuss an appropriately worded objective for this lab.

Apr 16­10:02 AM

With your partner, begin to design your experimental procedure. We will be conducting this lab during class on

Be sure to write up a materials list.

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Apr 16­10:05 AM

Procedures for Speeders LabMaterials needed:

How will measurement be done:

How will data be recorded:

Apr 17­8:23 AM

Sample Data Table

Car # Distance Time Speed Speed

1

2

3

4

5...

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Apr 17­8:28 AM

How many measurements will you need?

What else will you record? Do you think you'll see any other trends?

How will you calculate percentages? Will you just do percentagesoverall, or will you examine other variables?

Apr 17­8:29 AM

Any other questions, suggestions, etc.?