1. The problem statement, all variables and given/known data https://scontent-a-sjc.xx.fbcdn.net/hphotos-frc3/t1.0-9/10294335_1407511836191702_8633020308624670643_n.jpg 2. Relevant equations PE=.5kx^2 F=-kx 3. The attempt at a solution I honestly just dont know how to approach a problem where you have to find both the spring constant and the compression distance.... Ive tried employing conservation of momentum, ive tried working backwards with M1... Im pretty sure I need to find an equation that would solve for either K or x and then use that to find the other value. Am I on the right track?