A massless spring with spring constant k is placed betweena block of mass m and a block of mass 3m. Initially theblocks are at rest on a frictionless surface and they are heldtogether so that the spring between them is compressed byan amount D from its equilibrium length. The blocks arethen released and the spring pushes them off in oppositedirections. Find the speeds of the two blocks when theydetach from the spring.

A massless spring with spring constant k is placed betweena block of mass m and a block of mass 3m. Initially theblocks are at rest on a frictionless surface and they are heldtogether so that the spring between them is compressed byan amount D from its equilibrium length. The blocks arethen released and the spring pushes them off in oppositedirections. Find the speeds of the two blocks when theydetach from the spring.