1. A spring with a force constant k hangs vertically. A block of mass m is attached to the un-stretched spring and allowed to fall from rest. Find an expression for the maximum distance the block falls before it begins moving upward. 2. Now..from what i knw F=-kx (k=spring constant, x= extension) and i think it should be done like this: F=-kx mg=-kx x=-mg/k but i guess i did it wrong because my teacher did it in another very complicated way which i cannot understand. PLease see if you can help me. Solution: let da maximum distance be y. Total Mechanical evergy= total kinetic + total potential energy 0 = (1/2)mv^2 - mgy + (1/2)ky^2 and from here y was evaluated giving a result of y= 2mg/k My question is ..what is the total potential energy and y? What is the value of V, is it 0 , if yes, then y? and why is the total mechanical energy 0?