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Homework Help: Heat: efficiency

  1. Jun 28, 2003 #1

    Dx

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    A heat engine has efficiency of 35% and recieves 150J heat per cycle. how much work dos it perfrom in each cycle?

    I said 52.5J

    w=e*q_h =
    .35 * 150 =
    52.5
    its wrong

    what did i do wrong with this calculation. unless it mean 150J of put in. can anyone please explain this to me.
    TY!
    dx :wink:
     
  2. jcsd
  3. Jun 28, 2003 #2

    Tom Mattson

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    Can you post the definition of efficiency from your book?
     
  4. Jun 28, 2003 #3

    Dx

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    efficiency(e) = W(work out) / Q_H(work in)
     
  5. Jun 28, 2003 #4

    Tom Mattson

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    That's what I thought. OK, just plug-n-chug.

    (You know, it's always possible that the book is wrong!)
     
  6. Jun 28, 2003 #5

    Dx

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    I thought i did that like shown but aparently its not right. I just wanted to know does your answer match mine?
    Dx:wink:
     
  7. Jun 28, 2003 #6

    Tom Mattson

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    Yes, it does.
     
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