# Homework Help: Electromagnetic Induction and Faraday's Law

1. Feb 26, 2005

### airkapp

The generator of a car idling at 950 rpm produces 12.4 V. What will the output be at a rotation speed of 2500 rpm assuming nothing else changes?

I'm guessing that is easier and I'm looking to make it harder. I can't find anything in my textbook involving rpm. I'm thinkin to use this formula
E = NBAw but I'm actually not quit sure how to approach the problem.

is N my rpm? and then I do an initial rpm and final rpm sequence?

2. Feb 26, 2005

### vincentchan

N is number of loop... $$\omega$$ is the angular velocity.....

the rpm (rotation per minute, or radian per minute) is directly proportional to the angular velocity.... does that make sense to you?

3. Feb 26, 2005

### airkapp

so i could set this up as a proportion?

950/12.4 V =2500/x Volts ?

thanks.

4. Feb 26, 2005

### ramollari

I think you should also consider the back EMF.

5. Feb 26, 2005

### airkapp

sorry, I'm not following. If all things remain constant why would I consider that? The back emf oppose the motion (Lenz's law) correct, but if everything remains constant...