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Homework Help: Calculating work using hookes law

  1. Jan 13, 2010 #1
    1. The problem statement, all variables and given/known data
    Calculate the work done, in Joules for a system in which a muscle of 1cm^2 cross section and 10cm length is stretched to 11cm by hanging a mass on it. The muscle behaves like a spring. The spring constant for the muscle was determined by finding that the muscle exerts a force of 5.00N when it is stretched from 10.0cm to 10.5cm



    2. Relevant equations
    Is spring constant (-k) calculated simply by dividing .005m into 5.00N? (because F= -kx, and -k = F/x) = -1000.


    3. The attempt at a solution

    i dont think my answer will be correct because i have a feeling that im calculating k incorrectly??
    OK so assuming Im doing it right though...

    i set up the integral using hookes law:

    |work| = int (from .10m to .11m) -k (x - x0)dx

    = int (from .10m to .11m) -1000 (x - x0)dx
    then i took constants out of integral and integrated...

    |work| = -1000/2 * |from .10m to .11m [ (xf-x0)^2 - (xi - x0)^2]

    i dont want to proceed further unless i am on right track (which i doubt) thanks for any help!
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jan 13, 2010 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Right. k=1000*kg/s^2. Put units on the these numbers, ok? They aren't dimensionless. Now continue with the second part.
     
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