This isn't a homework question, just did a midterm and I am curious about a question. it had this diagram. Same initial speed. http://imgur.com/nsaDG and it asked which statement is most correct about the speed at height, h (the line going across the graph) a) It depends on their masses b) Ball 3 has smallest velocity c)All have same speed There were a couple other options, but I forget them, and these were the ones I was contemplating. I put that ball 3 has a lower speed because when it is at the height indicated the speed goes to zero. I also have another. Two carts sit on horiz. frictionless track. Equal masses. Cart A is moving towards cart B. Cart B is at rest. Is it ever possible for Cart A to move in reverse after the collision. a) depends on conditions of collision b) No, never c) Yes I put no, although I was thinking about that it depends on the conditions. I was thinking about if it was glues to the track, then it would go in reverse. But from what I know, the 2 cars either join together, one transfers all of its momentum to the 2nd, or they go off at different angles (since this is a horizontal track that wouldnt be possible).