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Homework Help: Linear thermal expansion

  1. May 16, 2005 #1
    Got this question wrong on this weeks physics quiz and can't figure out why. I keep getting the same answer - which was wrong - over and over. What am I missing?

    By how much will a slab of concrete 18 m long contract when the temperature drops from 24 °C to -16 °C? (The coefficient of linear thermal expansion for concrete is 10-5 per degree C.)
    Answers are in centimeters.
    change in length= a* Lo* change in temp
    Lo = 1800cm
    A = 10-5
    change in T = 24- (-16) = 40
    I keep coming up with .7 cm
    the answer was .5cm
    Where did I go wrong? Any help greatly appreciated
    Thank you
  2. jcsd
  3. May 16, 2005 #2
    I can't find an error in your calculations. Maybe the result was rounded in the answers or there's a typo somewhere?
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