Calculate Average Energy Use/Month

AI Thread Summary
The discussion focuses on calculating average energy use per month based on a power bill. A bill of $27.00 at a rate of 6.3 cents per kilowatt hour results in an average energy consumption of approximately 595.24 Joules per second. The conversation then shifts to determining the charge drawn by a 120 V air-conditioner, which accounts for about two-thirds of the total energy usage. This leads to a calculation of approximately 3.21 Coulombs per second for the air-conditioner. The calculations are confirmed to be accurate, with a note on the importance of significant figures.
NickCherryJiggz
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I'm helping a friend with this question and wanted to make sure I was doing it correctly...

Suppose your local power company charges 6.3 cents per kilowatt hour and your most recent bill came to $27.00. How much energy, on average, did you use (in Joules) per second last month? Assume that the billing period covered 30 days.

$27.00/($0.063/kilowatt hour) = 428.571428... kilowatt hours

428.57... * (3.6 x 10^6) = (1.5428571428571 * 10^9 Joules)/month = M

M / (30 * 24 * 60 * 60) = 595.23809523808 Joules/second

Thanks for the help!
 
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It's okay.U may want to learn the concept of significant figures,though...:rolleyes:

Daniel.
 
Thank you, Daniel...Sorry about the sigdigs.
I know these are just silly conversions for the most part, but could someone please verify the second half of the question as well?

Now pretend that roughly 2/3 of the energy usage last month was a result of a 120 V air-conditioner, how many Coulombs of charge per second did that air-conditioner draw?

595.24... * 2/3 = 396.83...J/s
V = J/C
120 Volts = (396.83... J/s) / (Coulombs/s)
3.21 Coulombs/second
 

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