Concepts (a) What force must be supplied by an elevator cable to produce an acceleration of 0.800 m/s2 against a 200-N frictional force, if the mass of the loaded elevator is 1500 kg? (b) How much work is done by the cable in lifting the elevator 20.0 m? (c) What is the final speed of the elevator if it starts from rest? (d) How much work went into thermal energy?

Step-by-step solution Step 1 of 5 Power is the rate at which work is done, or in equation form, for the average power P for work W done over a time t. The SI unit for power is the watt (W) here 1 watt equals 1 joule/second.