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.