Question

Texts: Air is contained in a well-insulated piston-cylinder assembly, initially at 1.5 bar with a temperature of 200°C and a volume of 0.002m^3. The top face of the piston is exposed to an atmospheric pressure of 1 bar; the piston has a mass of 20 kg and a face area of 0.01m^2. a. Are mechanical stops being used to hold the piston in place? If so, are they above or below the piston? If not, why are stops not required? b. Suppose the air is subjected to a polytropic process with pV^1.4 inside the well-insulated piston-cylinder assembly until the volume is halved. i. Calculate the work in kJ. Be sure to indicate whether the work is done on or by the system. ii. What is the change in internal energy of the gas in kJ?

          Texts: Air is contained in a well-insulated piston-cylinder assembly, initially at 1.5 bar with a temperature of 200°C and a volume of 0.002m^3. The top face of the piston is exposed to an atmospheric pressure of 1 bar; the piston has a mass of 20 kg and a face area of 0.01m^2.

a. Are mechanical stops being used to hold the piston in place? If so, are they above or below the piston? If not, why are stops not required?

b. Suppose the air is subjected to a polytropic process with pV^1.4 inside the well-insulated piston-cylinder assembly until the volume is halved.

i. Calculate the work in kJ. Be sure to indicate whether the work is done on or by the system.

ii. What is the change in internal energy of the gas in kJ?

Added by Elizabeth A.

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