2. Definition

3. Formula

4. Units

5. Momentum Vector quantity Direction matches direction of velocity

6. Example #1

9. Impulse equals change in momentum…

11. Example #2 A 1400 kg car moving westward with a velocity of 15 m/s collides with a utility pole and is brought to rest in 0.30 s. Find the magnitude of the force exerted on the car during the collision.

12. Example #2

13. Example #3 A 2250 kg car traveling to the west slows down uniformly from 20.0 m/s to 5.00 m/s. How long does it take the car to decelerate if the force on the car is 8450 N to the east? How far does the car travel during the deceleration?

14. Example #3

17. 4.00s

18. Practice 6C p213 #1-3 Right now in class…

19. Why are dashboards in automobiles padded? Longer time interval requires a smaller force to achieve same momentum change

20. When egg hits the plate the time period is shorter & force is greater

21. When the egg hits the pillow the time increases and the force decreases As the time increase, the force continues to decrease

22. Momentum and Collisions

23. Momentum is Conserved This section focuses on multiple objects interacting

24. Momentum is Conserved

26. Soccer Ball Example Q: How do the force exerted on ball A and the time interval compare with the force exerted on the ball B and its time interval? A: Forces are equal in magnitude and opposite in direction & time intervals are also equal.

27. Soccer Ball Example Q: How would you calculate the change in momentum of each ball? A:The change in momentum of each ball is equal in magnitude but opposite in direction because  P=F  t

28. Conservation of Momentum

29. Law of Conservation of Momentum: The total momentum of all objects interacting with one another remains constant regardless of the nature of the forces between the objects.

30. No! Only way for the final momentum to be zero is for the initial momentum to be zero! Initially both skaters would have to have the same momentum in opposite directions….

31. Momentum of the spacecraft & its fuel before the rockets are fired must equal the momentum of the two after the rockets are fired…

32. Momentum and Collisions

33. Example#4 Conservation of Momentum

35. Choose the formula:

36. Example #4

37. Practice 6D p219 #1-4

38. Perfectly Inelastic Collisions

39. Formula for Perfectly Inelastic Collisions

40. Example #5-Inelastic Collision

41. Elastic & Inelastic Collisions