How Do You Calculate Power Input for an Alternator at 3000rpm?

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To calculate the power input for an alternator running at 3000rpm with a sinusoidal output voltage of 100V, additional information such as the load resistance or current is necessary. The relevant equations include Ohm's Law (I=V/R) and Watts Law (P=VI), which require values for current or resistance to determine power input. The discussion highlights the importance of understanding Lenz's law regarding back EMF, which affects power calculations. Without sufficient data, the calculation cannot be completed. More information is essential for an accurate assessment of power input.
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Homework Statement


An alternator runs at 3000rpm and produces a sinusoidal output voltage with an amplitude of 100V. Calculate the power input required to turn it.


Homework Equations


Ohms Law: I=V/R, R=V/I, V=IR, Watts Law P = VI
Lenz's law regarding back EMF.

The Attempt at a Solution


I know I should be using the above formulas, but I cannot understand how to make the calculation with only the information that was provided. Can someone please help with the calculation.
Thanks kindly for any help.
 
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