일반물리학 1 — Potential Energy and Conservation of Energy: Problem 57

57 A block of mass 6.0 kg is pushed up an incline to its top by a man and then allowed to slide down to the bottom. The length of incline is 10 m and its height is 5.0 m. The coefficient of friction between block and incline is 0.40. Calculate (a) the work done by the gravitational force over the complete round trip of the block, (b) the work done by the man during the upward journey, (c) the mechanical energy loss due to friction over the round trip, and (d) the speed of the block when it reaches the bottom.