Energy Efficiency

While transmitting power or changing energy from one form to another,part of the power or energy is lost due to friction, radiation, etc. Hence, the out put is always lesser than the input. As such, energy efficiency is measured as ;-

Efficiency = out put of work / input of work

Example : 100 Revolutions of the handle are required to raise a load of 1000 kgf to a height of 5 m. Calculate the efficiency.

Output work = G x h = 1000 kgf x 5 m = 5000 kgfm
Input work = F x S = 20kgf x pi x 1m x 100 = 6280 kgfm
Efficiency = 5000/6280 = 0.8 = 80%