. What is the force in newtons exerted on the gas by the atmosphere, piston, and counterweight, assuming there is no friction between the piston and the cylinder? Answer: F = 1.91 x 10^4 N. b. What is the gas pressure in kPa? Answer: Pabs = 110.054 kPa. c. If the gas in the cylinder is heated, it expands, pushing the piston and counterweight upward. If the piston and counterweight are lifted by 0.83 m, what is the work done by the gas in kJ? What is the change in potential energy of the piston and counterweight? Answer: w = 15.848 kJ, and ΔEp = 1.222 kJ.
Kinetic Theory of Gas
The Kinetic Theory of gases is a classical model of gases, according to which gases are composed of molecules/particles that are in random motion. While undergoing this random motion, kinetic energy in molecules can assume random velocity across all directions. It also says that the constituent particles/molecules undergo elastic collision, which means that the total kinetic energy remains constant before and after the collision. The average kinetic energy of the particles also determines the pressure of the gas.
P-V Diagram
A P-V diagram is a very important tool of the branch of physics known as thermodynamics, which is used to analyze the working and hence the efficiency of thermodynamic engines. As the name suggests, it is used to measure the changes in pressure (P) and volume (V) corresponding to the thermodynamic system under study. The P-V diagram is used as an indicator diagram to control the given thermodynamic system.
A gas is confined in a cylinder with a diameter of 0.47 m by a piston, on which a counterweight rests. Together, the piston and the counterweight have a mass of 150 kg. The local gravitational acceleration is 9.813 m/s^2, and the atmospheric pressure is 101.57 kPa.
a. What is the force in newtons exerted on the gas by the atmosphere, piston, and counterweight, assuming there is no friction between the piston and the cylinder? Answer: F = 1.91 x 10^4 N.
b. What is the gas pressure in kPa? Answer: Pabs = 110.054 kPa.
c. If the gas in the cylinder is heated, it expands, pushing the piston and counterweight upward. If the piston and counterweight are lifted by 0.83 m, what is the work done by the gas in kJ? What is the change in potential energy of the piston and counterweight? Answer: w = 15.848 kJ, and ΔEp = 1.222 kJ.
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