1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Show that the work done in thermo

  1. Oct 23, 2005 #1
    hello the problem is as stated:
    a cylinder containing n moles of an ideal gas undergoes an adiabatic process. using [tex]W=-\int Pdv[/tex] and using the condition [tex]PV^\gamma=constant[/tex], show that the work done is:
    [tex]W=(\frac{1}{\gamma - 1}(PfVf - PiVi)[/tex] where Pf is final pressure, Pi is initial pressure...
    I tried substituting that [tex]P=\frac{constant}{V^\gamma}[/tex] into the integral, and evaluating from Vi to Vf, but this still leaves the gamma as an exponent. how can i go about solving this one?
  2. jcsd
  3. Oct 23, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Right, you have an exponential term that looks like [itex]V^{1- \gamma} [/itex]. Write this as a product of two terms, one of which is V itself. What can you do with the other part ?
  4. Oct 24, 2005 #3
    awesome thanks for your help. all i needed was to see it as 1-gamma, instead of how i had it as -gamma +1. it made a lot of difference.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook