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Homework Help: Finding the Spring Constant

  1. Feb 20, 2017 #1
    1. The problem statement, all variables and given/known data

    Force Extension in (m)
    1.0 0.014.
    1.5 0.032.
    2.0 0.053.
    2.5 0.071.
    3.0 0.090.
    3.5 0.110.
    4.0 0.130.
    4.5 0.148.
    5.0 0.166.

    2. Relevant equations
    F= kx.
    k=F/x,m= vertical side/ horizontal rise.

    3. The attempt at a solution
    I plotted a graph of force against extension and found the gradient to be 26.3N/m using the points (0.014,0.1) and (0.166,0.5).
    It's my understanding that the gradient should be equal to the answer obtained from k= F/x but when I work it out the answers are not similar and I'm not sure where I went wrong.
  2. jcsd
  3. Feb 20, 2017 #2
    Can you explain what that means. Does that mean that your answer is significantly different than the book?
  4. Feb 20, 2017 #3
    When I work it out it's not equal to the gradient which my teacher says it should be. I think it's because I'm not sure how to probably use the formula when there are so many quantities.
  5. Feb 20, 2017 #4
    I plotted the data. It appears that it doesn't intersect at x=0, F=0 very well. That has to be what is causing the discrepancy.
  6. Feb 20, 2017 #5
    Ooo I see my teacher has advised us that we could have started from 0.5 F instead of 0 instead as we were getting errors. Thank you I'll try to recover my previous set of data.
  7. Feb 20, 2017 #6
    That should help because if I find an equation for the line based on the 26.3 slope, it shows an offset of 0.63 N.
  8. Feb 20, 2017 #7
    Thanks again
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