1. Assuming the height of the hill is 50 m, and the roller-coaster car starts from rest at the top, calculate (a) the mechanical energy at the top of the hill (b) the speed of the rollercoaster car at the bottom of the hill, and (c) at what height it will have half this speed (calculated in letter d). Take h = 0 m at the bottom of the hill.(15 points)
