1. The problem statement, all variables and given/known data A massless spring of spring constant 20 N/m is placed between two carts. Cart 1 has a mass M1 = 5 kg and Cart 2 has a mass M2 = 3 kg. The carts are pushed toward one another until the spring is compressed a distance 1.3 m. The carts are then released and the spring pushes them apart. After the carts are free of the spring, what are their speeds? 2. Relevant equations K = 1/2 MV^2 F = -kX 3. The attempt at a solution Once I find out how to solve for one I'll know how to solve for both, so let's just deal with the 5 kg cart. Force in the Spring = 1.3 x 20 = 26 26 = 1/2 x (5) x V^2 10.4 = V^2 3.22 = V Wrong. I suspect I made this much simpler than it really is... where did I go wrong?