If an electric motor uses 50 kJ of energy to do 46 kJ of work, how efficient is it?
To calculate the efficiency of the electric motor, we can use the formula:
Efficiency = (Useful energy output / Total energy input) x 100%
In this case, the useful energy output is the work done by the motor, which is 46 kJ. The total energy input is the energy used by the motor, which is 50 kJ.
Therefore, the efficiency of the electric motor is:
Efficiency = (46 kJ / 50 kJ) x 100% = 0.92 x 100% = 92%
So, the efficiency of the electric motor is 92%.