1. The problem statement, all variables and given/known data A rubber ball of mass m = 0.225 kg is dropped from a height ho = 5.92 m, and it rebounds to a height hf = 4.58 m. Assume there is no air friction. Find J, the magnitude of the impulse exerted by the ground on the ball. 2. Relevant equations I = Ft Energy conservations formula: mgh or ½mv²? 3. The attempt at a solution Ugh... Don't think I have the right type of approach. -__- I first found that the energy lost is 2.96 J, which is right. I tried to use this form: mgh = ½mv² + ΔE But seems like there is no other way around.