Converting (having major trouble)

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Homework Help Overview

The discussion revolves around unit conversion, specifically converting kilowatt-hours (kWh) to joules (J) and understanding the relationship between watts, joules, and time. The original poster expresses confusion regarding the conversion process.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the conversion of energy units, with one suggesting a starting point by relating watts to joules per second. Others explore the calculation of joules in a kilowatt-hour and question the interpretation of costs associated with energy consumption.

Discussion Status

The discussion includes attempts to clarify the conversion process and the implications of the calculations. Some participants provide guidance on how to approach the problem, while others express uncertainty about the correctness of the calculations and the interpretation of costs.

Contextual Notes

Participants note that the task is part of homework intended for review before a quiz/test, which may impose certain constraints on how the problem is approached.

BunDa4Th
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I have a link to the image i am having trouble with it is D where i have to convert one SI unit, but really confuse how to do it.

http://img267.imageshack.us/img267/9623/webassignvy9.jpg

any help or explanation on how do the conversion would be very helpful.
 
Last edited by a moderator:
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Okay, I'll get you started. From your responses to the quiz, it is clear that you realize that:

1 W = 1 J/s

Therefore, 1 J = 1 W*s

A joule of energy is the amount of energy expended after one second by something that uses one watt of power.

Therefore

1 kWh = ? W*s

well, how many watts in a kilowatt? How many seconds in an hour? It's really as simple as that!
 
1 kWh = (10^3 W)(3600 sec.) = 3600000 W*s

BTW, its not a quiz it's homework given to us to review for the quiz/test.
 
Last edited:
Ok, hw. Cool...

So your answer looks right to me. In which case, if I'm reading your homework right, the cost is 7 cents per 3 600 000 joules = whatever

Let me know if that gives you the right answer!
 
7 cent is incorrect which i have tried earlier.
 
No no no! It's 7 cents for every kWh = 3600000 J. They want to know what it is on a PER JOULE basis. Now that you have the number of joules in a kWh, you can easily calculate the unit price PER JOULE.

cepheid said:
the cost is 7 cents per 3 600 000 joules = whatever

You were supposed to calculate the "whatever". That is your answer.
 
Last edited:

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