1. The problem statement, all variables and given/known data "A boy is initially seated on the top of a hemispherical ice mound of radius R = 13.8m. He begins to slide down the ice, with a negligible initial speed. Approximate the ice as being frictionless. At what height does the boy loose contact with the ice?" 2. Relevant equations PE = mgh KE = 1/2mv^2 PE + KE = constant 3. The attempt at a solution I have absolutely 0 clue what to do... to start, I equated PE and KE to get: mgh = 1/2mv^2 gh = 1/2v^2 h = 1/2v^2/g I do not think that's correct though... Any ideas on how to approach this?