1. Alex throws a 0.15-kg rubber ball down onto the floor. The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s. What is the change in the magnitude of the ball's momentum?
a. 0.09 kg m/s
b. 1.5 kg m/s
c. 4.3 kg m/s
d. 126 kg m/s
2. A ball with original momentum +4.0 kg m/s hits a wall and bounces straight back without losing any kinetic energy. The change in the momentum of the ball is:
a. 0
b. -4.0 kg m/s
c. 8.0 kg m/s
d. -8.0 kg m/s
3. 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
4. If the momentum of an object is tripled, its kinetic energy will change by what factor?
a. zero
b. one-third
c. three
d. nine
5. A moderate force will break an egg. However, an egg dropped on the road usually breaks, while one dropped on the grass usually doesn't break. This is because for the egg dropped on the grass:
a. the change in momentum is greater.
b. the change in momentum is less
c. the time interval for stopping is greater
d. the time interval for stopping is less
6. An elastic collision of two objects is characterized by the following:
a. Total momentum of the system is conserved
b. Total kinetic energy of the system remains constant
c. Both A and B are true.
d. Neither A nor B are true.
7. Two ice skaters push off against one another starting from a stationary position. The 45-kg skater acquires a speed of 0.375 m/s. What speed does the 60-kg skater acquire?
a. 0.500 m/s
b. 0.281 m/s
c. 0.375 m/s
d. 0 m/s
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