another resistence problem

[SparkimusPrime]

A question surprisingly similar to this:

http://www.physicsforums.com/showthread.php?t=17219

I = 1000amp
V = 700,000volt
distance = 100miles
Resistence of the wire = .5 ohm / mile

The resistence of my line is 50 ohms, original power is 7e5 * 1e3 = 7e8 watts. Final power, due to P = (I^2) * R, is 1e3^2 * 50 = 5e7 watts

So finding the difference:

7e8 - 5e7 = 6.5e8

The answer given by the teacher is 50 MW (50e6 watts right?). A math error I'm sure, anyone see it?

Peter

[Integral]

I am not sure why you are computing the difference.

The power lost by the line is

P=I2R

End of story, you do not even need to know the total power transmitted.

[Chen]

Maybe your teacher wants the power dissipated by the wire, and not the power that is left?

Beat me to it. :smile:

[SparkimusPrime]

Yes sorry, read the problem wrong. Seems to be a common failing with this book, using obscure english to mask the real problem.

Thanks.

Peter