Question

A farmer uses 3450 J of energy on a wheel and axle to lift a 15 kg bucket of water 20 m to the top of her well. What is the efficiency of the system?

Answer 1

Output= m*g*h = 15*9.8*20 = 2,940J

Input= 3450J (given)

Efficiency = output/input = 2,940/3450 = 0.85% efficient

Answer 2

Efficiency is the measure of how efficient a process is. It is used to assess the ability of a process in avoiding waste energy, materials, money and time in doing a desirable output. It is calculated as;

Efficiency = useful energy ouput / total energy input

Efficiency = 15(9.81)(20) / 3450 = 0.85