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!

Finding Final temp for Adiabatic process

  1. Oct 17, 2013 #1
    1. The problem statement, all variables and given/known data

    A nearly flat bicycle tire becomes noticeably warmer after it has been pumped up. Approximate this process as a reversible adiabatic compression. Assume the initial pressure and temperature of the air before it is put in the tire to be Pi = 1.00 bar and Tf 287K . The final pressure in the tire is Pf = 3.75 bar.

    Calculate the final temperature of the air in the tire. Assume that CV,m = 5R/2.
    2. Relevant equations
    dU=dw...as q=0 adiabaitc
    using these above equations my notes derive the following
    ViTic=VfTfc where c=Cvm/R
    PiVi[itex]\gamma[/itex]=PfVf[itex]\gamma[/itex] where gamma=Cpm/Cvm

    3. The attempt at a solution

    I am really stuck on where to even start this problem. It seems as if i am missing info, that i need a number of moles or a volume or something. I cant seem to find a way to rearange any of the above. In other problems it boiled down to using the boring old ideal gas pv=nrt to solve for one variable but again this leaves me with 2 unknows so im not sure what to do.

    Any tips, hints, explanations anything would be a great help!

    Last edited: Oct 17, 2013
  2. jcsd
  3. Oct 17, 2013 #2
    can i say that So im thinking can i say that
    (Tf/Ti)^c=Vi/Vf and (Pf/Vf)^(1/gamma)=ViVf

    so that (Tf/Ti)^c=(Pf/Vf)^(1/gamma)

    is this legit?
  4. Oct 18, 2013 #3


    User Avatar

    Staff: Mentor

    You have a couple of typos in there. Rewrite it more carefully.
  5. Oct 25, 2013 #4

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Try expressing the adiabatic condition in terms of T and P. Think of the air in the tire at the end as a compression of a much greater volume of air at atmospheric pressure into the final volume of the tire.

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Finding Final temp for Adiabatic process