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400 m/sec. 1 meter. A marksman holds his rifle perfectly horizontal and directs his fire straight over flat and level terrain. The rifle bullet leaves its barrel traveling at 400 m/sec. Once the bullet leaves the barrel it experiences. A . a forward force equal to its momentum.

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  1. 400 m/sec 1 meter A marksman holds his rifle perfectly horizontal and directs his fire straight over flat and level terrain. The rifle bullet leaves its barrel traveling at 400 m/sec. Once the bullet leaves the barrel it experiences A. a forward force equal to its momentum. B. a forward force equal to its weight. C. only the downward force of its weight. D. a forward force that is equal to its inertia.

  2. 400 m/sec 1 meter A marksman holds his rifle perfectly horizontal and directs his fire straight over flat and level terrain. The rifle bullet leaves its barrel traveling at 400 m/sec. How long is this bullet in the air? A. C. E. B. D. F.

  3. 400 m/sec 1 meter A marksman holds his rifle perfectly horizontal and directs his fire straight over flat and level terrain. The rifle bullet leaves its barrel traveling at 400 m/sec. The bullet is in the air for 0.45 seconds. How far down range does it strike ground? A. B. C. D. E.

  4. 400 m/sec 1 meter A marksman holds his rifle perfectly horizontal and directs his fire straight over flat and level terrain. The rifle bullet leaves its barrel traveling at 400 m/sec. The bullet is in the air for 0.45 seconds. It strikes the ground 180 meters down range. Another rifle with center-fire cartridges shoots bullets with twice the speed: 800 m/sec. They land down range after traveling A. the same the distance: 180 meters. B. the times as far: 254 meters. C. twice the distance: 360 meters. D. four times the distance: 720 meters.

  5. 1 2 1 2 Momentum = mass  velocity Kinetic energy = mass  (velocity)2 stopping time F t = (mv) Impulse: change in momentum stopping distance F d = ( mv2) Work: change in kinetic energy

  6. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. What was the car’s average speed while moving in contact with the wall? A. zero. B. 2 m/sec. C. 6 m/sec. D. 12 m/sec. E. 18 m/sec.

  7. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. Before impact the car had how much momentum? A. B. C. D.

  8. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. Before impact the car had how much kinetic energy? A. B. C. D.

  9. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. Before impact the car had 172,800 kg·m2/sec2 of kinetic energy 14,400 kg·m/sec of momentum. What was the force of impact on the car? A. 600 Newtons B. 5,880 Newtons C.14,400 Newtons D.28,800 Newtons E.172,800 Newtons F.345,600 Newtons

  10. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. Before impact the car had 172,800 kg·m2/sec2 of kinetic energy 14,400 kg·m/sec of momentum. How much time did it take the car to stop? A. 1/24 sec = 0.0417 sec B. 1/12 sec = 0.0833 sec C.1/6 sec = 0.1667 sec D. 1/4 sec = 0.2500 sec E.1/2 sec = 0.5000 sec

  11. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. Before impact the car had 172,800 kg·m2/sec2 of kinetic energy 14,400 kg·m/sec of momentum. What impulse did the car deliver to the wall? A. zero (no impulse). B. 14,400 kg·m/sec C.28,800 kg·m/sec D.86,400 kg·m2/sec2 E.172,800 kg·m2/sec2 F.172,800 Newtons

  12. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. Before impact the car had 172,800 kg·m2/sec2 of kinetic energy 14,400 kg·m/sec of momentum. How much work did the car do on the wall? A. zero (no work). B. 14,400 kg·m/sec C.28,800 kg·m/sec D.86,400 kg·m2/sec2 E.172,800 kg·m2/sec2 F.172,800 Newtons

  13. You temporarily lose control of your vehicle and crash headlong into a solid brick wall. The 600 kg car was traveling 24 m/sec, the front end has been pushed 1 full meter back into the frame. The wall didn’t move at all. Before impact the car had 172,800 kg·m2/sec2 of kinetic energy 14,400 kg·m/sec of momentum. Where did the kinetic energy of the car go? A.It is now stored in the bent metal parts of the car. B. It did work byslightly raising the center of mass of the car. C.It generated thermal energy within the car and wall. D.it was all transferred by the impulse to the wall.

  14. Having your head stopped by an airbag is safer than by the steering column because A. you would transfer more momentum to the steering wheel than you do to the airbag. B. you would transfer more energy to the steering wheel than you do to the airbag. C. you transfer the same momentum in either case, but it takes longer with the airbag. D. you transfer the same energy in either case, but the transfer takes longer with the airbag.

  15. A 10-kg sign hangs from two chains so that each chain shares the load equally. The weight borne by the individual eyelet fastener holding each chain at the top is A. 5 kilograms B. 10 kilograms C. (5 kg)(9.8 m/sec2) = 49 Newtons D. (10 kg)(9.8 m/sec2) = 98 Newtons E. between 49 – 98 Newtons.

  16. A simple pulley just redirects the lifting force.

  17. ??? F=? The force F an operator must apply by hand to hold this 200 lb weight in place is? The force F an operator must apply by hand to hold this 200 lb weight in place is? A. 50 lbs B. 100 lbs. C. 200 lbs. D. 250 lbs E. 300 lbs. F. 400 lbs. The hook in the ceiling holding the block and tackle in place, provides how much total force in support as this weight is lifted?

  18. The work by the operator holding this 200-lb weight in place is The work by the operator holding this 200-lb weight in place is A. positive. B. zero. C. negative. A.positive. B.zero. C.negative. F Raising this weight 6 feet with this block and tackle involves A.half the work raising it 6 feet by hand without the pulley. B.the same amount of work as raising it 6 feet by hand without the pulley. C.twice as much work as raising it 6 feet by hand without the pulley.

  19. This child lifts his basketfull of blocks by pulling with a force equal to A. ¼ its weight. B. ½ its weight. C. its weight. D. 2 its weight. E. 4 its weight. To raise it a distance h he must draw in what length of rope? A. ¼h B. ½h C.h D. 2h E. 4h

  20. 13 feet 5 feet 12 feet A crate is wheeled up a ramp into the back of a delivery truck, its wheels providing a smooth, almost friction-free ride. The workman must push forward with a force equal to A. (5/12)  the weight of the cart. B. (5/13)  the weight of the cart. C.(12/13) weight of the cart. D.the full weight of the cart. E. (13/12)  the weight of the cart. F. (13/5)  the weight of the cart.

  21. C. 26 feet 5 feet A. 8 feet B. 13 feet Several ramps of different length are available. A.Using ramp A requires the most work. B.Using ramp B requires the most work. C.Using ramp C requires the most work. D.The same amount of work is done using any of these ramps. When using the 26-foot ramp, the workman must push forward with a force equal to A. twice the force needed on ramp B. B.the same force needed on ramp B. C.half the force needed on ramp B. D.the full weight of the cart.

  22. When an object is pushed or pulled by a force that is completely balanced A. no work is possible. B. the kinetic energy of that object decreases. C. potential or thermal energy is produced as a consequence.

  23. In each of these examples the force being exerted by each worker is exactly balanced by another force! by elastic forces by weight by friction

  24. Lecture 11: 20 Questions 1. C only weight 2. D 0.45 sec 3. B 180 meters 4. C twice 5. D ½(24 m/sec) = 12 m/sec 6. B 14,400 kg·m/sec 7. C 172,800 kg·m2/sec2 8. E 172,800 N 9. B 1/12 sec 10. B 14,400 kg·m/sec 11. A zero 12. C thermal energy 13. C takes longer 14. C 49 N 15. B 100 lbs. 16. E 300 lbs. 17. B zero 18. B the same 19. A ¼ 20. E 4h 21. B (5/13) 22. D the same 23. C half 24. C potential and thermal energy It has 0.45 sec to move forward. It also has the same 0.45 sec to move forward. and d= 1 meter. vavg = 12 m/sec and d = 1 meter. impulse, Ft, = change in momentum. “The wall doesn’t move at all.” Same total Ft, but longer t. Mass is not weight. W = mg. There are 3 100-lb forces all pulling down. “to hold in place” means d=0. Total work still same: ¼F(4h)=Fh

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