Chapter 9. Lesson 2 How Do Objects React To Forces? How Do Forces Affect Motion?

Balanced & Unbalanced Forces Newton’s Laws of Motion

Chapter 9

Balanced & Unbalanced Forces

Lesson 2

Essential Question

How Do Objects React To Forces?

How Do Forces Affect Motion?

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Balanced Forces

If the forces acting on an object are balanced, the objects motion will not change.

Unbalanced Forces

When the sum of all forces acting on an object is unbalanced, the objects motion will change.

Explain How the Objects Can Be Balanced and Unbalanced

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Net Force - Page 338-339

Combination of all the forces on an object.

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Home Learning

Complete Lesson 2 Assess Your Understanding

Review & Assessment Page 349 #6-10

Vocabulary Lesson 2 Extra Credit: Magnet 2/24 Extra Credit: Gizmo #11 2/27

Newton’s Laws of Motion

Lesson 3

Essential Question

How Do Objects React To Forces?

What Is Newton’s First Law of Motion?

What Is Newton’s Second Law of Motion? What Is Newton’s Third Law of Motion?

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Newton’s First Law of Motion

An object at rest will remain at rest unless acted on by an unbalanced force.

An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

What does this mean? This means that there is a natural

tendency of objects to keep on doing what they're doing.

All objects resist changes in their state of motion.

In the absence of an unbalanced force, an object in motion will maintain this state of motion.

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Newton’s Second Law of Motion

Acceleration is produced when a force acts on a mass. The greater the mass the greater the amount of force needed.

FORCE = MASS x ACCELERATION

What does this mean? Everyone unconsciously knows the

Second Law. Everyone knows that heavier objects require more force to move the same distance as lighter objects.

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Newton’s Third Law of Motion

For every action there is an equal and opposite re-action.

What does this mean? This means that for every force

there is a reaction force that is equal in size, but opposite in direction.

That is to say that whenever an object pushes another object it gets pushed back in the opposite direction equally hard. 

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Guess Which Law of Motion

1st Law

2nd Law

3rd Law

Quick Question Quest1. Who was the scientist who gave us the Laws of

Motion? 

2. How many Laws of Motion are there? 

3. What is another name for the first law of motion? 

4. Which law explains why we need to wear seatbelts? 

5. Which law says that force is equal to mass times acceleration (F=MA)? 

6. Which law says that heavier objects require more force than lighter objects to move or accelerate them? 

7. Which law explains how rockets are launched into space? 

8. Which law says that for every action there is an equal and opposite reaction? 

Sir Isaac Newton 

Three 

Law of Inertia

First Law of Motion 

Second Law of Motion 

Second Law of Motion

Third Law of Motion 

Third Law of Motion 

Home Learning Complete Lesson 3 Assess Your Understandings

Review & Assessment Page 350 #11-15

Vocabulary Lesson 3 Extra Credit: Gizmo #11 2/27 Bring Roller Coaster Materials!