1. Aim: How do we explain Newton’s 3rd Law?

2. Newton’s Third Law
Whenever object A exerts a force on object B, object B exerts an equal and opposite force on object A. “For every action, there is an equal and opposite reaction”

3. Action-Reaction Force Pairs
Forces always come in pairs

4. Action-Reaction Force Pairs (Example 1)

5. Action-Reaction Force Pairs (Example 2)

6. Action-Reaction Force Pairs (Example 3)

7. True or False Problem 1
When you step on a roach, the roach applies an equal and opposite force on your foot as your foot applies to the roach (we don't advocate killing insects this way, especially if you are barefoot). TRUE

8. Problem 2
You and a friend are pulling on a rope in opposite directions as hard as you can. What is the "equal and opposite force" to the force of your hand pulling on the rope described by Newton's Third Law? a)The force of your arm pulling back on your hand b) The force of friction between the ground and your shoes c) The force of your friend pulling on the rope in the opposite direction d) The force of the rope pulling on your hand in the opposite direction e)The force of the rope pulling your friend's hand

9. True or False Problem 3
If you are an astronaut slowly drifting away from the space station, you might be able to drift back to the station by throwing a 555-kg tool rapidly in the direction that you are traveling (away from the station) TRUE

10. Draw the action-reaction forces on each (Example 1)
Below is a mother and son. The mother pushes off the son. a)Draw a vector representing the force the mother exerts on the son. b) Draw a vector representing the force the son exerts on the mother. c) Who experiences the greater force, the mother or the son? Same force on each d) Who accelerates more, the mother or the son? The son accelerates more because he has less mass

11. Draw the action-reaction force on each (Example 2)
A bottle rests on top of a table. Identify the action-reaction force pair. A bottle falls toward the ground. Identify the action-reaction force pair.

12. Regents Checkpoint
As a 500 Newton basketball player jumps from the floor up toward the basket, the magnitude of the force of her feet on the floor is 1000 Newtons. As she jumps, the magnitude of the force of the floor on her feet is
500 N
1000 N
1500 N
500,000N

13. Write Up
If the Sun attracts the Earth with the same force that the Earth attracts the Sun, why does the Earth move around the Sun (as opposed to the Sun moving around the Earth? The earth has less mass so it accelerates more due to the gravitational force than the sun will.