Solving for Pressure in Four Cylinder Thermodynamic Problem

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Homework Help Overview

The discussion revolves around a thermodynamic problem involving four cylinders, specifically focusing on calculating pressure and volume under various conditions. The original poster is attempting to solve a problem related to pressure using the formula P=F/A and the ideal gas law PV=nRT.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the application of force balance and the types of thermodynamic processes involved, such as isobaric, isothermal, and adiabatic processes. There are questions about the correct equations to use for calculating volume and pressure in different states.

Discussion Status

Some participants have made progress in solving parts of the problem but are still exploring the relationships between pressure and volume. There is a mix of interpretations regarding the appropriate equations to apply, and guidance has been offered on using force balance and the ideal gas law.

Contextual Notes

Participants are navigating constraints related to the changing temperatures and the nature of the processes involved, which affects their approach to solving for volume and pressure. There is an acknowledgment of potential errors in previous calculations.

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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?
 
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.
 
Ok my answer to the volume are wrong, do I use P1V1=P2V2 or do I use PV=nRT equation ?
 
can anyone help please ? I've figured out pressure, but I'm stuck on how to find volume
 
I think you should use P1V1=P2V2, that is supposed to work when T=constant.
 
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 ?
 
alex1261 said:
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 ?

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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