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Homework Help: Maximum force that we can exert without breaking the rope?

  1. Jan 12, 2010 #1
    1. The problem statement, all variables and given/known data

    If we want to pull a block with a weight of 5N attached to a rope that is just able to resist 20N. What is the maximum force that we can exert without breaking the rope? xD

    2. Relevant equations

    Fnet (in y) = ma = F (applied force) - W (weight)

    3. The attempt at a solution

    What I think is that: if the rope will just resist 20, and we already know that the weight of the block is 5N, then we should apply a 15N force right ?
     
  2. jcsd
  3. Jan 12, 2010 #2

    rock.freak667

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    Re: Forces.

    You want the net force to be less than or equal to 20N. Knowing W=5N, what is the applied force you should apply?
     
  4. Jan 12, 2010 #3
    Re: Forces.

    actually, this is a problem that I had on a test some days ago...I think that was the question in fact. What force I should apply ?...
     
  5. Jan 12, 2010 #4

    rock.freak667

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    Re: Forces.

    The maximum net force is 20N, using your relevant equation, what would the applied force?
     
  6. Jan 12, 2010 #5
    Re: Forces.

    25n ?
     
  7. Jan 12, 2010 #6

    rock.freak667

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    Re: Forces.

    That seems correct.
     
  8. Jan 12, 2010 #7
    Re: Forces.

    thanks xD
     
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