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Homework Help: Mechanical work problem

  1. Oct 25, 2008 #1
    1. The problem statement, all variables and given/known data

    2 men lift a total mass of 653.2 kg 4in off the ground a total of 24 times. Estimate the total mechanical work done by the 2 men in lifting the boat 24 times, assuming they applied the same force to the boat during each lift. (Neglect any work they may have done allowing the boat to drop back to the ground.)

    2. Relevant equations
    w=f*d


    3. The attempt at a solution
    w=f*d
    First convert kg to newtons 653.2*9.8=6401N and inches to meters 4in=.102m
    I tried the f*d and came up with 653 and then multiplied that by 24 and got 15672. The answer in the back of the textbook gives 2x10^4 J and I cannot figure it out.
     
  2. jcsd
  3. Oct 25, 2008 #2
    I suppose you are expected to give the answer with only one significant digit. The height (4 in) has only one digit so the answer should have one SD too.
     
  4. Oct 25, 2008 #3
    No if you read my post the answer the textbook gives is 2*10^4J and I cannot figure out how to get the answer
     
  5. Oct 25, 2008 #4
    Your answer it is 2x10^4 if you round it to one significant digit.
     
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