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Homework Help: Thermodynamic Problem

  1. Feb 25, 2010 #1
  2. jcsd
  3. Feb 25, 2010 #2

    rock.freak667

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    At state 2, when the mass is in equilibrium, you need to do a force balance. Remember F=PA. Then look at the temperatures of states 1 and 2. What type of process is that?
     
  4. Feb 26, 2010 #3
    Thanks ! i have managed to solve a and b but now i am stuck on c I believe the answer to c is isobaric, because P=F/A is not affected by the growing volume nor the temperature. and it can't be isothermal because the temperature is changing. and I don't quite understand how adiabatic works.
     
  5. Feb 26, 2010 #4
    Ok my answer to the volume are wrong, do I use P1V1=P2V2 or do I use PV=nRT equation ?
     
  6. Feb 28, 2010 #5
    can anyone help please ? I've figured out pressure, but i'm stuck on how to find volume
     
  7. Feb 28, 2010 #6

    rock.freak667

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    I think you should use P1V1=P2V2, that is supposed to work when T=constant.
     
  8. Feb 28, 2010 #7
    yeah I was considering that. And to find the volume in state 4, I would have to use PV=nRT correct ? since T isn't constant ?
     
  9. Feb 28, 2010 #8

    rock.freak667

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    From state 3 to 4, it looks like T=100°C for both 3 and 4. So while you can use PV=nRt at 4, you should be able to use P3V3=P4V4 as well
     
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