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Homework Help: Thermodynamics Ideal Gas Problem

  1. Nov 8, 2008 #1
    1. The problem statement, all variables and given/known data
    An ideal gas expands from the state (p_1, V_1 ) to the state (p_2, V_2 ), where p_2 = 2p_1 and V_2 = 2V_1. The expansion proceeds along the straight diagonal path AB shown in the figure.

    Find an expression for the work done by the gas during this process.
    Express your answer in terms of the variables p_1 and V_1.

    2. Relevant equations
    W = (p_1 V_1 - p_2 V_2) / (y - 1)

    3. The attempt at a solution
    I put the equation exactly with y = 1.4.
    Masteringphysics says "Your answer either contains an incorrect numerical multiplier or is missing one.".

    What have I done wrong?
  2. jcsd
  3. Nov 18, 2008 #2
    Is that an equation from a textbook? Don't think about trying to apply an equation. Instead, use theory and some common sense.

    You state in the problem that there is a figure that you don't show. It does sound like you have a pressure vs volume plot where there is a straight line from p1,V1 to p2,V2.

    With that, work is basically the area under that line. Calculate that area for work.
  4. Nov 19, 2008 #3
    I have managed to solve this problem. Thank you.
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