help i'm really stuck on this question! A skier starts from rest at the top of a hill. The skier coasts down the hill and up a second hill. The crest of the second hill is circular, with a radius of r = 45 m. Neglect friction and air resistance. What must be the height h of the first hill so that the skier just loses contact with the snow at the crest of the second hill? um. i know it has to do with 1/2m(vf)^2+mghf=1/2mv0^2+mgh0 but i just don't really understand what the question meant by 2nd hill and its radius!!!!