The higher level has a rough section of length L. After passing this section the block slides head on into a spring. The block momentarily stops after compressing the spring by d. The block initial speed is vo, the height difference is h, and the coefficient of kinetic friction is μ.
1) Determine the spring constant k.
2) In terms of the other given variables (m, h, L, μ, and d), find the minimum value of vo in order for the block to return to its original position.