Walker, Halliday & Resnick — Kinetic Energy and Work: Problem 49

49 A fully loaded, slow-moving freight elevator has a cab with a total mass of $1200\text{ kg}$, which is required to travel upward $54\text{ m}$ in $3.0\text{ min}$, starting and ending at rest. The elevator's counterweight has a mass of only $950\text{ kg}$, and so the elevator motor must help. What average power is required of the force the motor exerts on the cab via the cable?