일반물리학 1 — Potential Energy and Conservation of Energy: Problem 42

42 A worker pushed a 23 kg block 8.4 m along a level floor at constant speed with a force directed 32° below the horizontal. If the coefficient of kinetic friction between block and floor was 0.20, what were (a) the work done by the worker’s force and (b) the increase in thermal energy of the block–floor system?