1. The problem statement, all variables and given/known data A spring is compressed by 0.100m from its equilibrium position, and two blocks of masses 3kg and 5kg are resting motionless on each side on a frictionless surface. The spring has a force constant of 20 N/m, and a rope holds the block in position against the compressed spring. If the rope is cut, the spring drives the blocks apart - find the resulting speed of each block. 2. Relevant equations Ee (elastic energy) = 1/2kx^2 Ek(block 1 or 2) = 1/2mv^2 3. The attempt at a solution I know that the elastic energy of the spring will be equal to the kinetic energy of the blocks as they move and am fine with solving Ee=Ek, and isolating for v. However, my problem is that I'm not sure whether my Ee for each block is Ee/2 (would the energy be divided evenly between the blocks?), so basically - whether my force constant (k) should be divided by two (20/2)- and if whether the 0.100m compression should also be divided by two, since when the spring is released, I'm thinking the displacement should be equally divided on either side. As far as the change in force constant, I've read that if a spring is cut in half, its k value is actually doubled - but i'm not sure if this situation can be likened to that in which the spring is cut in half. And I cannot figure out for sure whether compression should be divided in half or not. Please help!