An electrical motor has a power rating of 500 W when it is lifting a mass of 80 kg through a height of 6 m in a time of 15 s. Calculate the efficiency of the motor?

Answer 1

F = ma = 80kg * 9.8 m/s^2
W = Fd = F * 6m
P = W/s = W / 15s

P = 80*9.8*6/15 = 313.6 W

Now you can figure the % eff.