1. The problem statement, all variables and given/known data http://www.screencast.com/users/ntrinh3/folders/Jing/media/a4165a56-de0d-4a4a-a01e-49242fd505c4 Need help with question 13 2. Relevant equations Conservation of energy and momentum occurs in elastic collision 3. The attempt at a solution Why would the block 2 have an increase in energy? The velocity of block 2 will now be positive instead of negative but velocity is squared anyway. The computer's answer was A. Increase, but shouldn't it remain the same?