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Thermodynamics: Adiabatic Compression

  1. Apr 30, 2009 #1
    1. The problem statement, all variables and given/known data

    The engine of a Ferrari F355 F1 sports car takes in air at 20.0 *C and 1.00 atm and compresses it adiabatically to 0.0900 times the original volume. The air may be treated as an ideal gas with [tex]\gamma[/tex] = 1.40.

    Find Final Temp and Final Pressure


    2. Relevant equations

    Equation 1
    T1V1[tex]\gamma[/tex]-1=T2V2[tex]\gamma[/tex]-1

    Equation 2
    P1V1[tex]\gamma[/tex]=P2V2[tex]\gamma[/tex]


    3. The attempt at a solution

    Solving Equation 1 for T2 gives:
    T2= T1(V1/V2)[tex]\gamma[/tex]-1

    Solving Equation 2 for P2 looks the same, except it is only raised to [tex]\gamma[/tex]

    The value for V1 isn't know, but V2=.09V1

    I substituted this value of V2 into Equation 1, and canceled V1 (because it was divided by itself), and got the answer of 54.4. This number is way too low, because this is an engine we're talking about.

    I'm not sue how to continue the problem. Do I need to take a square root (or I guess in this case the "gamma root"), to cancel out the gamma exponent, and solved for V1?
     
  2. jcsd
  3. Apr 30, 2009 #2
    You know:

    V1 and V2 as you know the compression ratio from V2 = 0.09 V1. The actual values dont matter, its only the ratio that does. So you can set V1 to 1.

    From this you can find T directly.

    Hint:

    What temperature scale are you meant to be using?
     
  4. Apr 30, 2009 #3
    It's supposed to be in Kelvin? I feel dumb now.

    I got them both. Thank you for your help.
     
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