Spring Compression problem!- PLEASE SOMEONE HELP! PLEASE!!! DX<? Spring Compression problem! A 2.4kg block is dropped onto a free-standing spring with k=1100N/m from a height of 1.7m above the spring. What is the spring's maximum compression? Okay, so I drew a picture of the situation. Frame #1: Falling Block: kinetic energy, but no potential energy Spring: No kinetic energy and no potential energy Frame #2: Block has now compressed the spring to the maximum it is able. Block and Spring: potential energy, but no kinetic energy (If this reasoning is wrong so far, please let me know what is wrong about it and why! Thanks! :D) So: Energy in Frame #1 = Energy in Frame # (Kf + Uf) = (Ki + Ui) [0 + 1/2(k)(x^2)] = [1/2(m)(v^2) + 0] ([1/2(1100)(x^2)] = [1/2(2.4)(5.77)^2] x = .2695m I found the velocity for this equation by: (vf)^2 = (vi)^2 + 2ad Vf= 5.77m.s So that was how I found the max. compression of .2695m... But in class, my teacher got the answer: .29m He wrote the equation for this problem as: mgh + mgx = 0 + 1/2(k)(x)^2 How does he have 2 potential energies on the left side of the equation?! The block is moving! Wouldn't there be just a kinetic energy??? Please help me! Can the problem be done as I have done it, or is this wrong? Please explain WHY it is wrong, if that is so. Thank you SO much! :D You are awesome!!!