An elevator weighing 2,200 lbs is raised one story in 20 seconds. if the distance between stories is 10 feet, the power developed by the elevator motor is ft • lb/s. the power of the motor required for the elevator is h. p.

To calculate for the power developed in the elevator motor in ft.lb/s, we multiply the distance and the weight of the elevator and divide the product by the time.
                       Power = (10 ft)(2200 lb) / 20 s = 1100 ft.lb/s

Next, convert the calculated value to HP. 
                              1100 ft.lb/s x (1 HP/ 550 ft.lb/s) = 2 HP