1. The problem statement, all variables and given/known data A block os mass m is attached to a horizontal spring, which is attached to a wall. The block is oscillating without friction with initiation amplitude A0 and maximum velocity v0. When the block is at its maximum amplitude (and therefore instantaneously at rest), is it struck by a second identical block, moving to the left at velocity v0, and the collision is completely inelastic. What is the ratio of amplitudes after and before the collision A / A0 2. Relevant equations E = (1/2)kA0^2 = (1/2)kx^2 + (1/2)mv^2 m1v1 + m2v2 = (m1 + m2)v' 3. The attempt at a solution I first set up my conservation of momentum equation to determine v' after the collision: 0 + mv0 = 2mv' v' = v0/2 I then tried to use my energy equation to solve for final amplitude, where the energy of the system after the collision is equal to the kinetic energy from the incoming block and the potential energy of the original system. E2 = (1/2)(2m)(v0/2)^2 + (1/2)kA0^2 = (1/2)kA^2 Rearranging and simplifying, I've narrowed it down to: kA^2 = (mv0^2)/2 + kA0^2 But I don't know how to get the ratio from this equation. Is there something else I should be plugging in to substitute and simplify?