1. Newton’s 3rd Law of Motion

2. For every action there is an equal and opposite reaction
Newton’s 3rd Law
For every action there is an equal and opposite reaction

3. Examples Hammer and Nail:
As a hammer hits a nail, the hammer applies a force to the nail AND the nail applies a force on the hammer this is why the hammer slows down as it hits the nail
Rocket blasting off the launch pad:
As the rocket applies a thrust force downward, the rocket moves upward

4. ALL FORCES COME IN PAIRS They are known as: “action-reaction pairs”

5. “Action-Reaction Pairs”
Object A applies an “action” force on Object B while at the same time Object B has a “reaction” force on Object A of equal magnitude but opposite direction.

6. That’s a lot to write out…
It can be shortened with a formula! 
FAB = -FBA
In English this simply says the Force that Object A puts on Object B is equal but opposite (remember: the negative just means opposite direction) to the Force that Object B puts on Object A

7. Ever try to jump with your legs straight the entire time?

8. Why is it so difficult? There is no action-reaction pair!
You need the bending “action” to have the jumping “reaction”.

9. Think, pair, share (Think about it yourself, talk it over with a partner, and then write your ideas in your notes):
Use Newton’s 3rd Law of Motion to explain to a classmate why it hurts when you punch a wall.

10. Can a wall really punch you back?
YES! Well, in a way…

11. How?
The wall applies a force that is exactly equal in magnitude but opposite in direction.
This “reaction” force is known as a negative force; remember the negative just refers to the fact that it is opposite in the direction it goes

12. Check YOUR Understanding
A truck driving down the road hits a mosquito. The mosquito is smashed and the truck continues driving.
Which of the two forces is greater: The mosquito on the truck or the truck on the mosquito? Why?
(Hint: really think about Newton’s 3rd Law here and maybe even think back to Newton’s 2nd Law to answer “why?”)

13. When you think you have the answer…
Use your Peer-to-Peer Network to ask a classmate (that has already completed this question) if your answer matches theirs 