When work is done on an object, energy is transferred. Power is the amount of work done in one second. Efficiency is a measure of how much useful energy is converted.
Part of Physics (Single Science)Energy
How much energy does the motor transfer every second?
Power is the amount of energy transferred in one second.
The power of the motor is 26.8 W and so it transfers 26.8 J of energy every second.
A wind generator has an output power of 2.5 MW.
How long does it take to generate 250 GJ of electrical energy?
power = \(\frac{\text{energy transferred}}{\text{time taken}}\)
time taken = \(\frac{\text{energy transferred}}{\text{power}}\)
power = 2.5 MW = 2.5 x 1,000,000 W = 2,500,000 W
(1 MW = 1,000,000 W)
energy transferred = 250 GJ = 250 x 1,000,000,000 J = 250,000,000,000 J
(1 GJ = 1 000 000 000 J)
time taken = \({250,000,000,000 J}\div{2,500,000 W}\)
time taken = 100,000 s
100,000 s = \({100,000}\div{60}\) = 1666.7 minutes
1667 minutes = \({1667}\div{60}\) = 27.8 hours.
It takes the wind generator 27.8 hours.