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Hookes law and Youngs modulus

  1. Nov 18, 2013 #1
    1. The problem statement, all variables and given/known data

    Consider a metal bar of initial length L and cross-sectional area A. The Young's modulus of the material of the bar is Y. Find the "spring constant" k of such a bar for low values of tensile strain.

    Express in terms of Y, L, and A.
    2. Relevant equations

    I know the hooks law equation and the modulus but i can't figure out the answer it wants me ot get

    Maybe i'm doing it wrong but i am getting Y/(L*A)...
    3. The attempt at a solution
  2. jcsd
  3. Nov 18, 2013 #2


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    Spring constant = F/ΔL .........................(1)

    Youngs Mod. Y = F/ΔL * L/A .......................(2)

    Rearrange (2) to give an equation for F/ΔL

    Substitute into 1
  4. Nov 18, 2013 #3
    im getting F=(Y*A)/L
  5. Nov 18, 2013 #4


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    You are close but the answer isn't the force F = (Y*A)/L

    The problem asks you to work out an equation for the spring constant k.
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