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Homework Help: Just needed to be proofread (easy forumula)

  1. Jun 16, 2007 #1
    1. The problem statement, all variables and given/known data
    A screw pump is turned with a force of 125N. The handle traces a circle with a DIAMETER of 30cm, and is turned 45 times. The pump lifts 130 litres of water 2m high. (1 litre of water = 1kg aka 10N)
    What is the work output?
    What is the work input?
    What is the efficiency of the pump?

    2. Relevant equations

    3. The attempt at a solution
    For work output, i did: 130 times 10 = 1300N times 2M = 2600J
    Work output: 2600J

    For work input, i did Pi times .30m = .94m times 45 = 42.4M times 125N = 5300J
    Work input: 5300J

    Effiiciency: 2600J divided by 5300J = 49%

    Is this correct?
  2. jcsd
  3. Jun 16, 2007 #2


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    Homework Helper
    Gold Member

    Looks good to me!
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