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Physics Thermodynamic problem

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

    Frensley_Thermo_PV-Diagrams_012a.gif Frensley_Thermo_PV-Diagrams_012b.gif Frensley_Thermo_PV-Diagrams_012c.gif Frensley_Thermo_PV-Diagrams_012d.gif

    A cylinder has a base area of 0.016 m2 and is fitted with a piston that can freely move. Below the piston, the cylinder is filled with gas that has a pressure P1 = 106000 Pa, a volume V1 = 0.0014 m3, and a temperature of T1 = 0 ° C when in state 1. The gas is then taken through the following four-step process:
    • An m = 30 kg metal block is placed on top of the piston, compressing the gas to state 2, with the gas still at T2 = 0 ° C.
    • The cylinder is then put in contact with a boiling water bath, raising the gas temperature to T3 = 100 ° C in state 3.
    • The metal block is then removed and the gas expands to state 4, still at T4 = 100 ° C.
    • Finally, the cylinder is placed in contact with an ice-water bath, bringing the gas back to T1 = 0 ° C in state 1.

    (a) Determine the pressure of the gas in state 2.


    (b) Determine the volume of the gas in state 2.


    (c) Determine the volume of the gas in state 4.


    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations
    I'm not sure which equations to use


    3. The attempt at a solution
    The metal block on top of the piston is confusing me, any help would be appreciated.
     
  2. jcsd
  3. Jan 17, 2013 #2

    ehild

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    What relation holds for an ideal gas between P, V, T? The box on the piston means additional pressure of mg/A.

    ehild
     
  4. Jan 17, 2013 #3

    rude man

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    Is the piston weightless?
     
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