Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ideal Gas Cycle

  1. Oct 30, 2010 #1
    1. The problem statement, all variables and given/known data

    How much heat is added over this cycle? During which processes?
    What is the heat expelled from d to a?

    2. Relevant equations

    http://img838.imageshack.us/img838/6270/29494670.png [Broken]
    (Goes clockwise, abcda)

    3. The attempt at a solution

    I'm just generally confused overall about this question. Is heat added in the processes which are going "forward"? So would heat only be added during processes a-b and b-c?

    And would I use Q = dU + W to calculate the heat added for the processes?

    For the 2nd question, for heat expelled, would I still just use Q = dU + W to find it?
    So Q = nCvdT + pdV to find the heat expelled for process d to a.

    Thanks for any clarification and help, I am really lost here.
     
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Oct 31, 2010 #2
    Anyone?
     
  4. Oct 31, 2010 #3

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Hi. Yes, you would use Q = ΔU + W to get the heat added or expelled for each path segment. Q is positive for heat added, and negative when heat is expelled.
     
  5. Oct 31, 2010 #4

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    How does the temperature at c compare to the temperature at b? Use that to determine the heat flow from b-c.

    How is the net work done by the system related to the heat in and heat out?

    AM
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook