a motor is rated at 2238W and is 93% efficient . how much power must be supplied to the motor?
2007-10-04 07:02:59 · 3 answers · asked by slim8880 1 in Science & Mathematics ➔ Mathematics
Think about the problem like this.
If the motor were 100% efficient, it would give out all of the energy it took in. Therefore 2238W in will be sufficient for the power out rating of 2238W. But no physical system runs at 100% efficiency (hence perpetual motion is impossible!).
So we are looking for an answer of more than 2238W, and the answer is found by dividing the rating by the efficiency, in this case 2238/93=2406W.
Whoever decided on a figure of 93% efficiency for this problem, or any other involving an electromechanical device, has a very optimistic approach!
2007-10-04 07:20:14 · answer #1 · answered by netruden 2 · 0⤊ 0⤋
2238/.93
2007-10-04 14:30:35 · answer #2 · answered by car 3 · 0⤊ 0⤋
=2238/0.93 W
2007-10-04 14:11:05 · answer #3 · answered by Anonymous · 1⤊ 0⤋