d = 10+5 = 15m
Power = Workdone/time
Power = (Force * distance)/time Since Workdone = F * d
Power = (m * g * d)/time Since Force = m * g
Power = (720 * 10 * 15)/1
Power = 108000W
(ii) Since half an hour is an hour divided by 2, then the workdone in (i)will be divided by 2. So,
108000W/2 = 54000J
m = mass, g = acceleration due to gravity, d = distance