Two blocks are free to slide along a frictionless wooden track. A block of mass m1=5 kg is released from point A. Protruding from its front end is the north pole of a strong magnet, repelling the north pole of an identical magnet embedded in the back end of the block of mass m2=10 kg, initially at rest. The two blocks never touch. Calculate the maximum height to which m1 rises after the elastic collsion. m1 is initially at a height of 5 meters. I don't know what equation to use for this problem.