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Homework Help: Thermal expansion on a spring?

  1. Nov 20, 2007 #1
    1. A brass spring has an unstrained lenght of .18m and a spring constant of 1.3 E4 N/m. THe temperature increases from 21 cel to 135 cel. what is the magnitude of the compressional force that must be applied to the heated spring to bring it back to its original lenght!?

    2. Linear expansion; Change of lenght= constant *lenght * change of temp
    F= K Change of lenght

    the thing i am concern is with Linear expansion formula can i use this fromula for the spring?! I figure out my change of lenght first my multyplying my coeficcient of brass
    (9*10^-6)* .18m * 135-21 to get a result of 3.89*10^-4

    Then i clicked it on to the spring constan formula using F= 1.3*10^4 * the distance of 3.89*10^-4 to myforce of 5.07N... is this a right approach?
  2. jcsd
  3. Nov 21, 2007 #2
    Must be correct.I don't think that this question needs more complicated solution.
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