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Homework Help: Work question: please check my work

  1. Dec 6, 2004 #1
    If a certain horse can maintain 1.00hp of output for 2 hrs, how many 70 kg bundles of shingles can the horse hoist to the roof of a house 8 m tall, assuming 70% efficiency?

    He're what I did: 1 hp = 745.7 W = 44742 J/min = 2684520 J/hr = 5369040 J/ 2 hr * 70% = 3758328 J / 2 hr

    W=Fd
    W=(70*9.8)(8m)
    W=5488 J

    3758328 J / 5488 J =684.8 bundles of shingles

    is this correct?
     
  2. jcsd
  3. Dec 6, 2004 #2
    The working is right - so if u calculated the numbers properly - you should get the right answer.
     
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