CHAPTER 13

Momentum

1 . Two spheres traveling in opposite directions collide head-on as shown. The graph shows the force
between the spheres during the collision. The velocity of the 10 kg sphere after the collision is
(A) 1 m/s to the left.
(B) 1.75 m/s to the left.
(C) 1.75 m/s to the right.
(D) 4 m/s to the left.
(E) 5 m/s to the right.

2 . A skateboard rolls under a tree at a constant velocity; a cat drops vertically out of a tree and lands on
it. The skateboard and cat move off together. Which of the following statements is correct?
(A) The skateboard speeds up because the cat adds kinetic energy to the system.