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  1. Dec 7, 2009 #1
    1. The problem statement, all variables and given/known data

    A steel rod 4.00 cm in diameter is heated so that its temperature increases by 70.0 C. it is then fastened between tow rigid supports. The rod is allowed to cool to its original temperature. Assuming that Young's modulus for the steel is 20.6 * 10^10 N/m^2
    and that its avarege coefficient of linear expansion is 11 * 10^-6 1/C , Calculate the
    tension in the rod.

    2. Relevant equations

    Delta L = L1 * alfa ( avarege coefficient of linear expansion ) * delta T

    and

    F / A = Y delta L / L

    3. The attempt at a solution

    I found delta L / L from first law above

    then i found tension from second law

    Is this true ?? please i need the answer today

    Best wishes for you
     
  2. jcsd
  3. Dec 7, 2009 #2
    please help me

    today the last time for answer
     
  4. Dec 8, 2009 #3

    Redbelly98

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    Your method is correct.
     
  5. Dec 8, 2009 #4
    But i doubt in my method because the rod's length will decrease by cooling

    and it will exert force on supporter

    and my equation for solution contain avarege coefficient of linear expansion

    not for compression .... understand me ?
     
  6. Dec 8, 2009 #5

    Redbelly98

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    The coefficient of expansion applies equally to the case of cooling/contraction.
     
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