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Homework Help: Efficiency of leg muscles.

  1. Apr 7, 2013 #1
    Please refer to the image attached.

    For Q5, I did it like this:

    Output energy = (50kg x 10 x 0.35metre) x 30times x 4minutes

    And divide the answer by 120kJ.

    The percentage I got is 17.5 Joules but the answer is 15J.

    Did I do anything wrong?

    For Q6, the temperature should fall, correct?

    Thanks in advance.

    Attached Files:

  2. jcsd
  3. Apr 8, 2013 #2


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    Homework Helper

    The muscles did work and produced heat. So the input energy is work+heat. The efficiency is output energy divided by input energy.

  4. Apr 8, 2013 #3
    But there are no informations about heat.
  5. Apr 8, 2013 #4


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    Read the problem text: "The muscles generate 120 kJ heat".

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