1. A 3.1 kg cart is traveling at 7.12 m/s to the right and it has a head on elastic collision with a 11.7 kg cart traveling at 1.12 m/s to the left. If the final velocity of the first cart is 1.263 m/s to the left, what is the final velocity of the second cart?

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?