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Homework Help: Thermodynamic- Internal energy of dry air

  1. Mar 1, 2012 #1
    1. The problem statement, all variables and given/known data
    a) what is the density of dry air when the surface pressure is 1010hPa and the temperature is 27°C.

    b) what is the internal energy of 1kg of dry air under these conditions?

    2. Relevant equations
    P=p*R*T where P is pressure and p is density.

    3. The attempt at a solution
    a) p = RT/P by solving it gives me
    [287*(273+27)] / 101000 => 0.852kg/m

    can someone please check what i did for part (a) is right or not?

    b) i don't really get where to go with this question. So some help would be really appreciated thanks!
  2. jcsd
  3. Mar 1, 2012 #2


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    Think it over...

  4. Mar 1, 2012 #3
    OH my bad! should be p=P/RT right?

    and hint for part b please
  5. Mar 1, 2012 #4


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    Last edited: Mar 1, 2012
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