A block of mass m starts at rest at height h on a friction less inclined plane. The block slides down the plane, travels across a rough horizontal surface with coefficient of kinetic friction μ, and compresses a spring with force constant k a distance x before momentarily coming to rest. Then the spring extends and the block travels back across the rough surface, sliding up the plane. The block travels a total distance d on rough horizontal surface. The correct expression for the maximum height h’ that the block reaches on its return is:
