Throwing Balls in Carts

Think about the question below. Only one of the answers listed is correct. We'll do some (but probably not all) of these questions in the lectures when you will all be asked to vote on which answer you think is correct. (Soon afterwards, you'll be able to see your responses, and those of the whole class at EVAF.)

Suppose you are on a cart, initially at rest on a track with very little friction. You throw balls at a partition that is rigidly mounted on the cart. If the balls bounce straight back (as in the figure) is the cart put in motion?
Graphic - No title - rocketball
1
Yes, it moves to the right.
2
Yes, it moves to the left.
3
No, it remains in place.