1. The problem statement, all variables and given/known data Assume there is no air friction. A ball of mass m = 3.39 kg is dropped from rest at height h = 1.51 m. It hits the ground, losing energy ΔE = 1/11 of its total energy in the collision. How high will the ball bounce upward before it comes momentarily to rest? 2. Relevant equations U = mgh KE = ½mv² 3. The attempt at a solution mgh = ½mv_f² [At the start before the first bounce] v_f = √(2gh) ≈ 5.44 m/s ½mv_f² = 10/11 * mgh_n where h_n is the new height h_n = 11/20 * v_f²/g ≈ 1.66 m, which is wrong.