Consider two carts moving along a track. Cart1 is moving much more quickly than cart 2. Bother carts 1 and 2 have some clay attached to their ends. Cart 1 catches up to cart 2 and collides with it. they stick together and the two carts move to the right at a speed in between the initial speeds of carts 1 and 2. Which of the following is the complete evidence that the two carts were involved in a contact push/pull interaction?

Which one of the following g/r energy diagrams best describes the interaction between the two carts in the previous problem?