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Homework Help: Area of Thermal Expansion

  1. Sep 27, 2012 #1
    1. The problem statement, all variables and given/known data
    A non-isotropic material is heated, fractional increase in length is different along different directions. With length l1=6.1 cm and l2=6.0 cm. In direction of l1, the coefficient expansion is [itex]\alpha[/itex]1= 10×10-5 K-1 and direction l2 is [itex]\alpha[/itex]2= 40×10-5K-1. The plate is heated until it becomes a perfect square. What is the area of the square? (The answer is 38 cm2) I just don't know how use the equations with out a given temperature.

    2. Relevant equations

    3. The attempt at a solution
    Not sure what to do with the equations without the temperature.
  2. jcsd
  3. Sep 27, 2012 #2
    You need to find the temperature from the condition that the rectangular becomes square.
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