1. The problem statement, all variables and given/known data One end of a vertical spring of spring constant k = 1900 N/m is attached to the floor. You compress the spring so that it is 2.50 m shorter than its relaxed length, place a 1.00-kg ball on top of the free end, and then release the system att = 0. (All values are measured in the Earth reference frame.) A. By how much does the mass of the spring change during the time interval from t = 0 to the instant the ball leaves the spring? B. By how much does the mass of the Earth-ball-spring system change during the time interval from t = 0to the instant the ball reaches its maximum height? 2. Relevant equations ΔE=Δmc2 Us=1/2 kx2 3. The attempt at a solution ΔE=ΔU=1900/2×2.52=5937.5 Δm=5937.5/9/188=6.597×10-6 is this correct for question A? I'm not sure if the mass changes because the instant the ball leaves the potential energy is converted to the ball's kinetic energy. And there should be no change in mass? For question B, how should I approach?