1. The problem statement, all variables and given/known data A block of mass 1.20 kg is placed in contact with a spring with a force constant of k = 2.20 N/m. When released, the spring pushes the block and expands a distance of 0.420 meters. If the floor is frictionless, the speed of the block as it leaves the spring is ? m/s. 2. Relevant equations Elastic energy is Ue = .5kd2 Energy in a block-spring system is E = .5kx2 + .5mv2 3. The attempt at a solution Well the problem is I haven't been able to get anywhere, because in my obviously incorrect thinking, if the block has yet to be released, then all the energy is potential, so E = Ue, but if E = Ue, then .5kx2 = 0, which can't be right. So, in short, I really don't know what I'm doing here. Am I using the wrong equations or something?