(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Warm air is contained in a piston-cylinder assembly oriented horizontally. The air cools slowly from an initial volume of 0.003m^3 to a final volume of 0.002m^3. During the process, the spring exerts a force that varies linearly from an initial value of 900N to a final value of zero. The atmospheric pressure is 100kPa, and the area of the piston face is 0.018m^2. Friction is neglected between piston and cylinder. For the air, determine the initial and final pressures and work.

2. Relevant equations

Pressure x Area = Force

Work = [tex]\int[/tex] p dV

3. The attempt at a solution

Initial Pressure of Air x Area = Atmospheric Pressure x Area + Spring Force

Initial Pressure of Air x 0.018m^2 = (100x10^3Pa x 0.018m^2) + 900N

Initial Pressure of Air = 150kPa

Final Pressure of Air x Area = Atmospheric Pressure x Area

Final Pressure of Air = Atmospheric Pressure

Final Pressure of Air = 100kPa

Work = [tex]\int[/tex] p dV

Volume is changing from 0.003m^3 to 0.002m^3, which can be used as an interval of this integration. I am not sure about how I should use pressure to calculate the work.

Also, I am not really sure if I got those pressures correctly.

Thank you.

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# Homework Help: Thermo Problem

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