1. Newton’s Third Law and Momentum

2. Newton’s Third Law
According to Newton’s third law of motion, whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object

3. Newton’s Third Law cont.
“For every action, there is an equal and opposite reaction”

4. Action and Reaction Forces
The action force is the force that has motion The reaction force is the force that reacts to the motion

5. Action and Reaction cont.
Example: When hanging a picture, you use a hammer to drive a nail into the wall. The hammer strikes the nail, it applies a force to the nail (action) The nail also applies an equal and opposite force to the hammer (reaction force)

7. Action and Reaction Forces Cont.
Not all action and reaction forces result in motion Simply pushing against a wall creates action and reaction forces

8. Momentum
Momentum is the product of an object’s mass and its velocity

9. Momentum cont.
Objects with large momentums are harder to stop than objects with little momentum Example: it is harder to stop a moving car than to stop a person walking

10. Momentum cont.
An object has a large momentum if its velocity is large and it has a large mass An object has a small momentum if its velocity is small and it has a small mass

11. Momentum cont.

12. Calculating Momentum
To calculate momentum you multiply an object’s mass and its velocity Momentum = Mass x Velocity

13. Calculating Momentum
Example: A bowling ball weighs 7kg and has a speed of 6 meters per second Momentum = 7kg x 6 m/s Momentum = 42 kg(m/s)

14. Conservation of Momentum
In a closed system, the loss of momentum of one object equals the gain in momentum of another object

15. Conservation of Momentum

16. Conservation of Momentum

17. What are we doing? Momentum Worksheet (Due end of hour)
Vocabulary (Due Monday)
Answer the “Assessment” questions on pg 377
Read ahead: Universal Forces pg