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Homework Help: Average Power of a sled

  1. May 14, 2007 #1


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    1. The problem statement, all variables and given/known data

    A sled is being pulled along a horizontal surface by a horizontal force F of magnitude 600 N. Starting from rest, the sled speeds up with acceleration 0.08 m/s^2 for 1 minute.

    Find the average power P created by force F.

    2. Relevant equations

    P = Fs/T

    3. The attempt at a solution

    So I need to first find displacement of movement. If y = .08x^2, then at 60 seconds y = 288 .... so displacement is 288 right?

    The force is 600 N
    so since P = Fs/T, then (600*288)/60 should be my answer right? Also would this answer be in watts? I know that 1 joule/second = 1 watt.
  2. jcsd
  3. May 14, 2007 #2
    Apart from a tiny factor of 1/2, everything else is right. Yes, the SI unit of power is the Watt. Can you find where you missed the factor? :wink:
  4. May 14, 2007 #3


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    So y = (1/2).08x^2

    this would yield a displacement of 144
    so then (600*144)/60

    would be a better answer?

    Also this answer is in joules so I need to multiply the whole thing by 60 to yield watts right?

    so my final answer in watts should be 600*144 ????
  5. May 14, 2007 #4
    That is the correct answer.

    As I said, there was nothing wrong with your first answer apart from that 0.5. It is Newtons.metre/second -> Joule/second -> Watt. Moreover, why would you take the trouble of first dividing and then immediately multiplying by 60?
  6. May 14, 2007 #5


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    ack! :blushing: :blushing: :redface:

    Thanks buddy! I appreciate the help!
  7. Jul 15, 2007 #6
    is power factor good or bad? Why?

    Im just not sure!
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