A block of mass m slides along a smooth track from one level to a higher level after passing through an intermediate valley. 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.
a) Find the block's velocity when it reaches the higher level.