"Joseph B. Reid" wrote:
>
> John Kilopascal wrote in USMA 19089:
>
> >. The power formula for DC
> >(P=EI) is modified when used with AC. The factor of cosine of the angle
> >between the current and voltage must be taken in account. If the voltage
> >and current are in phase, then the power is the equal to the voltage times
> >the current as in a DC circuit becaue the difference in angle is zero and
> >the cosine of zero is one. If the voltage and current are pi rad out of
> >phase, then the cosine of pi is zero and the power is zero too, even if we
> >were talking about a megamp time a megavolt
>
> I think he meant pi/2 radians instead of pi radians.
OK, but what on Earth did he mean by "megamp"? ;-)
Jim
--
Metric Methods(SM) "Don't be late to metricate!"
James R. Frysinger, CAMS http://www.metricmethods.com/
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