Hi, my question is this: A solid ball with mass M, radius R, speed U0, angular speed W0 hits a wall at the angle theta0. after the hit, the ball goes away with an angle theta1, angular speed W1 and speed U1. i'm asked to find the angular momentum for the point of hit, before and after the hit. i'm also asked to find the neccesary conditions of U0, W0, and theta0 so that the path of the ball after the hit would be 90 degrees from the wall. I've been trying for some time now to crack this question but no luck... any tips, ideas would be extremely helpful!