1. Newton’s Third Law of Motion
Chapter 6
Action and Reaction

2. Question:
Is it possible for me to touch the table but not have the table touching me?

3. 6-1 Forces and Interactions
A force is a push or pull.
Forces do not act alone. Forces are mutual actions called INTERACTIONS between two things.

4. For example… A hammer hits a nail…
The nail interacts with the hammer. The hammer hits the nail and the nail hits the hammer.

5. 6.2 Newton’s Third Law
“Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first”

6. In other words…
“For every action there is an EQUAL and OPPOSITE reaction”

7. 6.3 Action vs. Reaction For example: One Force (an action):
Pushing on a wall
Second Force (a reaction):
The wall pushing back

8. What happens to you when you jump off a boat onto the shore?
What happens to the boat?

9. 6.3 Action and Reaction “ACTION” happens first:
Driving in a car, the tires push on the road.
Dropping a book, the Earth pulls on the book.
“REACTION” happens second:
The road pushes back on the tires.
The book pulls back on the Earth.

10. 6.4 Action and Reaction on Different Masses
FORCES
are equal even if
MASSES
are different.

11. 6.4 Action and Reaction on Different Masses
The force exerted on a cannon is equal to the force exerted on the cannonball
So, why does the cannonball move so much faster and farther than the cannon?

12. 6-5 Why don’t they cancel each other out?
Page 78-79
Figure
Do the action and reaction act on the same object?
If so, they can cancel each other out.

13. Action VS Reaction opposite in direction Equal in magnitude and
Forces do not cancel each other out.

14. 6.6 The Horse-Cart Problem
Observe the pairs of forces acting on the horse and cart

15. 6.7
ACTION = REACTION
Example: Pushing on a wall vs
Punching a wall

16. Chapter 6 Newton’s 3rd Law of Motion Vocabulary:
1. action force 3. Newton’s 3rd Law
2. interaction 4. reaction force