1. CHAPTER 4 FORCES and the LAWS of MOTION

2. 4.1 The Newton’s First Law: The Law of Inertia

3. TODAY’s OBJECTIVES Understand what the Newton’s First Law means
Understand and explain what does INERTIA mean
Determine the net external force on an object

4. The Newton’s First Law - The Law of Inertia
An object at rest remains at rest
An object in motion continues in motion with constant velocity (constant speed in a straight line) UNLESS a net external force is applied
INERTIA!

5. WHAT IS INERTIA? If an object at rest resists being moved.
you have to produce a tremendous push to get it moving
Mass is a measure of INERTIA

6. 2. If an object is moving, it resists a change of speed or direction
WHAT IS INERTIA?
2. If an object is moving, it resists a change of speed or direction

7. Can You Explain and Demonstrate INERTIA?
Using only what you are given and anything on your desk:
Explain it in on a worksheet using full sentences + FBDs
AND
Find 3 ways to demonstrate inertia

8. How Can You Explain What INERTIA Is Using These Pictures?
property of resisting a change in motion is called inertia

9. How Can You Explain What INERTIA Is Using These Pictures?
When we flick the ring, the ring moves fast whereas the coin continues in its state of rest and hence drops into the cup.

10. The Newton’s First Law - The Law of Inertia
An object at rest remains at rest
An object in motion continues in motion with constant velocity (constant speed in a straight line) UNLESS a net external force is applied
In other words…

11. The Newton’s First Law - The Law of Inertia
When the net external force on an object is 0, the object’s acceleration is 0 (the velocity is constant)
WHAT IS THE NET FORCE?

12. The Newton’s First Law - The Law of Inertia

13. Classwork Page: 105 - 107 Problems: Investigation 4 -1
(#1, 2, 4, and 6)

14. HOMEWORK
Page: 108
Problems: all