10-1: The Nature of Force

How do balanced and unbalanced forces affect an object’s velocity?

Anticipatory Set

Put a book on your desk.Move the book.

Did you push or pull?Can it move without a push or pull?

California StandardsScience Standard 8.2.a: Students know a

force has both direction and magnitude.Science Standard 8.2.c: Students know

when the forces on an object are balanced, the motion of the object does not change.

Inputforce: a push or a pull.newton: the SI unit for the magnitude, or

strength of a force.net force: the combination of all forces

acting on an object.unbalanced forces: will cause the velocity of

an object to change.balanced forces: equal forces acting on one

object in opposite directions.

Input & ModelingWhat Is a Force?

A force is described by its magnitude and by the direction in which it acts.The newton (N) is the SI unit of force. It is

named after the English scientist and mathematician Isaac Newton.

You exert about one N of force when you lift a small apple

The longer the arrow, the greater the force.Arrows can show direction

and strength of a force

Input & ModelingCombining Forces

Input & ModelingUnbalanced Forces

Unbalanced forces acting on an object result in a net force and cause a change in the object’s velocity.

Unbalanced Forces in the Same Direction: When two forces act in the same direction, the net force is the sum of the two individual forces.

Input & ModelingUnbalanced Forces

Unbalanced Forces in the Same Direction

Input & ModelingUnbalanced Forces

Unbalanced forces acting on an object result in a net force and cause a change in the object’s velocity.

Unbalanced Forces in the Opposite Direction: When two forces act in opposite directions, the net force is the difference between the two individual forces.

Input & ModelingUnbalanced Forces

Unbalanced Forces in the Opposite Direction

Input & ModelingBalanced Forces

Balanced forces acting on an object do not change the object’s velocity.

Balanced Forces in Opposite Directions: When two equal forces act in opposite directions, they cancel each other out.

Input & ModelingBalanced Forces

Balanced Forces in Opposite Directions

iPad ExplorationFlorida Website: Weekly Standards

Lesson 10-1 Activity (in class on iPads)

1. Click on the link and take notes about Force in the "rules" box of your notes. Force Activity (rules)

2. Click on the link and read about Direction and Size of Forces. Complete the "Activity" on your whiteboard. Direction of Force Activity

3. Click on the link, read, and take notes about Balanced & Unbalanced Forces. Balanced and Unbalanced Forces Activity Complete the "Activities" at the bottom of the page. The Calculating net force requires a paper from Mrs. Chase, Balanced or unbalanced? is done on the iPad. You may complete Balancing man at home for fun if you would like.

HOMEWORK CONNECTION Read pages 374-377 in your Science textbook.

Complete the Section 10-1 Review & Reinforce

Write a detailed SUMMARY of the section and complete the UNANSWERED QUESTIONS section of your notes.

Choose two of the remaining Depth & Complexity ICONS in your notes and explain how they relate to this section.