PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A winch supports a 200kg crate at rest, holding it motionless 15m above the ground. In one second, the winch’s cable reels in a negligible length so that the crate’s height is unchanged and its speed remains zero. Explain whether the winch’s power output during that second must be zero, and justify your answer in one or two sentences.