16. A 75-kg swimmer dives horizontally off a 500-kg raft. : 2102135
16. A 75-kg swimmer dives horizontally off a 500-kg raft. If the diver's speed immediately after leaving the raft is 4 m/s, what is the corresponding raft speed?
A. 0.2 m/s
B. 0.5 m/s
C. 0.6 m/s
D. 4.0 m/s
17. A cannon of mass 1 500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 45? above the horizontal. Find the recoil velocity of the cannon across the level ground.
A. 1.33 m/s
B. 0.94 m/s
C. 2.41 m/s
D. 1.94 m/s
18. The law of conservation of momentum is applicable to systems made up of objects described by which of the following?
C. interacting through friction
D. All the above choices are valid.
19. A machine gun is attached to a railroad flatcar that rolls with negligible friction. If the railroad car has a mass of 6.25 ´ 104 kg, how many bullets of mass 25 g would have to be fired at 250 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?
B. 2 000
C. 3 000
D. 5 000
20. Ann the Astronaut weighs 60 kg. She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s. What speed does this give Ann as she moves toward the shuttle?
A. 4.0 m/s
B. 5.3 m/s
C. 8.5 m/s
D. 9.0 m/s