External pressure on a piston with/without friction

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SUMMARY

The discussion focuses on analyzing the relationship between external pressure on a piston and the effects of friction during gas compression and expansion in a cylinder. The key equations referenced include P = F/A and W = P*Delta(V), which relate pressure, force, and work. The contributor, ehild, asserts that the work done is proportional to F*Delta(V) and remains constant regardless of the direction of piston movement due to the energy loss from friction. The challenge lies in accurately sketching the graphs of the ratio F/A as a function of volume V during these processes.

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  • Understanding of gas laws and thermodynamics
  • Familiarity with the concepts of pressure and work in physics
  • Knowledge of frictional forces and their impact on mechanical systems
  • Ability to interpret and create graphs based on mathematical relationships
NEXT STEPS
  • Study the principles of thermodynamics, focusing on the first law and its application to gas systems
  • Learn about the effects of friction on mechanical work and energy transfer
  • Explore graphical representation of pressure-volume relationships in gas laws
  • Investigate the role of sliding friction in piston-cylinder systems
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Students studying physics, particularly those focusing on thermodynamics and mechanics, as well as educators seeking to clarify concepts related to pressure, work, and friction in gas systems.

Dishsoap
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Homework Statement



"A gas is enclosed in a cylinder with a piston of area A. The relation between the pressure and volume of the gas at a constant temperature T is shown in Figure B. On a similar figure, sketch graphs of the ratio of the external force F to the area A, F/A, as a function of V, as the gas is (1) is slowly compressed, and (2) is slowly expanded at the temperature T. Ther is a force of sliding friction f between the piston and the cylinder.

The image is similar to
Ideal_gas_isotherms.png



Homework Equations



P = F/A
W = P*Delta(V)

The Attempt at a Solution



All I did was say that the work is proportional to F*Delta(V). I think that the work would be the same in both cases, since the work done by friction would remove remove energy from the system regardless of which direction the piston is moving. From there, I don't know how to draw the graph.
 
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Read the problem text again. Does it ask the work?

ehild
 

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