2. We will be playing Jeopardy today! Please come up with a team name and write it on the board above your team number.

3. Concepts: Momentum Concepts: Impulse 200200 Problems: Collisions Level II Problems: Impulse Concepts: Collisions Problems: Collisions Level I 1000 800 600 400 200 400 600 800 1000 800 600 400 200

4. Is momentum a vector or a scalar? Back And the answer is..

5. And the answer is... Vector!! (since momentum is mv and velocity is a vector, momentum is a vector) Back

6. What are the units for momentum? And the answer is...

7. kg m/s Back

8. What two things must an object have in order to have momentum? Back And the answer is..

9. And the answer is... Mass and Velocity Back

10. Speed and momentum are ________ related. (fill in with directly or inversely) Back And the answer is..

11. And the answer is... directly Back

12. True or false: a more massive object always has more momentum than a less massive object. Back And the answer is..

13. And the answer is... False! If the less massive object has a great enough speed, it can have more momentum. Back

14. What are the 2 possible units for impulse (give two answers) Back And the answer is..

15. And the answer is... kg m/s or Ns Back

16. An object experiences a change in momentum, does it experience an impulse? Back And the answer is..

17. And the answer is... Yes!! Impulse is defined as the change in momentum. Back

18. What are the two equations for impulse? Back And the answer is..

19. And the answer is... J = m(vf – vi) J = Ft Back

20. What is the symbol (not unit) for impulse? Back And the answer is..

21. And the answer is... J Back

22. When an airbag is employed, the person feels the same impulse than if the airbag were not employed. Why then does an airbag reduce injury (relate your explanation to impulse). Back And the answer is..

23. And the answer is... Because the time is increased. Using J = Ft, if J is remains the same, but F is decreased, t must be increased for to remain the same. The impulse is felt over a longer period of time, resulting in a weaker force. Back

24. What is conserved in all collisions? Back And the answer is..

25. And the answer is... Momentum! Back

26. Two cars stick together as a result of a collision, what type of collision occurred? Back And the answer is..

27. And the answer is... Inelastic Back

28. What type of collisions conserve kinetic energy? Back And the answer is..

29. And the answer is... Elastic! Back

30. When a gun is fired, which experiences the greatest change in momentum, the gun recoiling or the bullet? Back And the answer is..

31. And the answer is... They both experience the same change in momentum…momentum is ALWAYS conserved. The bullet will have a greater velocity than the recoil of the gun b/c the bullet has a smaller mass, but the overall momentum will be conserved. Back

32. State what type of collision loses energy and explain WHY. Back And the answer is..

33. And the answer is... Inelastic collisions lose energy because friction and thermal energy are involved during crumpling/deformation of the objects. Back

34. And the answer is.. A 10-N force acts for 4 seconds on a 10-kg block as shown above. Determine the impulse delivered

35. And the answer is... J = Ft = (10 N)(4 s) = 40 Ns Back

36. A 8-N force is applied to a 3-kg ball to change its velocity from +5 m/s to +12 m/s. The impulse is encountered by the ball for a time of ____ seconds Back And the answer is..

37. And the answer is... 2.6 seconds Back

38. A 1,000-kilogram car traveling at 12.0 meters per second hits a tree and is brought to rest in 0.15 second. What is the magnitude of the average force acting on the car to bring it to rest? Back And the answer is..

39. And the answer is... 80,000-N Back

40. A force of 50 N acting for 0.1 seconds would provide an equivalent impulse as a force of 12 N acting for how many seconds? Back And the answer is..

41. And the answer is... 0.42 seconds Back

42. A 145-g baseball pitched at 38.0 m/s is hit on a horizontal line drive straight back toward the pitcher at 52.0 m/s. If the contact time between the bat and ball is 0.0012 s. Calculate the average force between the ball and bat during contact. Back And the answer is..

43. And the answer is... - 10,875 N Back

44. A 10,000-kg car traveling east at 12 m/s collides With an identical car at rest. The two couple Together as a result of the collision. Determine Their common speed after the collision. Back And the answer is..

45. And the answer is... 6 m/s Back

46. And the answer is.. If the two blocks above stick together as a result of the collision, what is their common speed afterward?

47. And the answer is... - 2 m/s Back

48. A 150-kg cannon at rest contains a 12-kg cannon ball. When fired, the cannon ball leaves the cannon with a speed of 90 m/s. What is the recoil speed of the cannon? Back And the answer is..

49. And the answer is... 7.2 m/s Back

50. A 45.0-kg child standing stationary on a skateboard throws a 4.5-kg ball horizontally with a speed of 2.0 m/s. Calculate the resulting velocity of the skateboard. The mass of the skateboard is 6-kg. Back And the answer is..

51. And the answer is... - 0.18 m/s Back

52. A 5.0-kg ball traveling at 6.0 m/s collides head-on with a 3.0-kg ball moving in the opposite direction at a speed of 8.0 m/s. If the 5.0-kg ball bounces backward at 4.0 m/s after the collision, find the speed of the second ball after the collision. Back And the answer is..

53. And the answer is... 8.7 m/s Back

54. What two equations can be used to find values involved in elastic collisions? And the answer is..

55. And the answer is... COM: m1v1i + m2v2i = m1v1f + m2v2f COE: v1i + v1f = v2i + v2f Back

56. A ball of mass 3-kg moving with a speed of 4.0 m/s collides head-on with a 1.2-kg ball at rest. If the collision is perfectly elastic, what will be the speed and direction of each ball after the collision? And the answer is..

57. And the answer is... 1.7 m/s and 5.7 m/s Back

58. A 0.023-kg bullet traveling at 230 m/s embeds itself in a 2.5-kg stationary pendulum. To what height will the pendulum swing? Back And the answer is..

59. And the answer is... 0.22 m Back

60. A 5-kg block going 6 m/s collides elastically with a 8-kg block heading in the opposite direction at 4 m/s. Determine the direction and velocity of each block after the collision. And the answer is..

61. And the answer is... V1f = -6.3 m/s V2f = 3.7 m/s Back

62. Determine the initial velocity of a 17-g bullet that when fired into a 2.9-kg stationary pendulum embeds itself and causes the pendulum to rise 8.0-cm. And the answer is..

63. And the answer is... 215 m/s Back