1. The problem statement, all variables and given/known data 2. Relevant equations (Conservation of momentum) (Conservation of energy) 3. The attempt at a solution I know linear momentum must be conserved on the X-axis, so mvo=mv1x+Mv2 where v1 is the final velocity of the small mass and v2 is the final velocity of the large mass. Also, M=2m. Energy is also conserved, so (1/2)mvo2=(1/2)mv12+(1/2)Mv22+mgR Since the problem stipulates that the 2 blocks never lose contact with each other, I'm guessing the momentum in the x direction would actually be mvo=(m+M)v2 and v2=v1x But I'm not sure if that is right, and so I'm not totally sure where to go from here.