10- = The 50-kg block rests on the rough surface for which the coefficient of kinetic friction is uk 0.2. A force F = (40+ s²) N, where s is in m, acts on the block in the direction shown. If the spring is originally unstretched (s = 0) and the block is at rest, determine the power developed by the force the instant the block has moved s = 1.5 m. 30 3 k-20lb/ft