A vertical spring with constant 200N/m has a light platform on its top. When a 500-g mass is set on the platform, the spring compresses 0.0245m. The mass is now pushed down 0.0755m farther and released. How far above this latter position will the mass fly? The answer from the book. If it does, Us at start=Ug at end, where zero Ug is at its lowest position. 200(0.10)2/2=0.5(9.8)h ............................ I'm not sure if i intepret it correctly. Initial spring energ=highest level it goes. But if the KE energy is transformed to PE, what additional energy to make it 'fly'? Thank You.