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sodium.dioxid
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In a cylinder (with a piston) containing gas, why do we use the external pressure, instead of the pressure of the gas, to calculate work?
Why do we use external pressure to calculate work in gas cylinders?
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SUMMARY
In gas cylinders, external pressure is used to calculate work instead of internal pressure because internal forces cancel each other out, making external pressure a more stable reference. The work done by the gas during expansion is defined by the equation dW = p dV, where p represents external pressure. For isothermal expansion, the work can be calculated using the formula Work = nRT ln(V2/V1), derived from the ideal gas law PV = nRT. This approach simplifies understanding the work done on the system by the surroundings.
PREREQUISITES- Understanding of thermodynamics principles, specifically gas laws.
- Familiarity with calculus, particularly integration techniques.
- Knowledge of pressure concepts in physics.
- Basic understanding of piston-cylinder systems in thermodynamic processes.
- Study the ideal gas law and its applications in thermodynamics.
- Learn about isothermal and adiabatic processes in gas expansion.
- Explore the derivation and applications of the work done formula in thermodynamics.
- Investigate the differences between internal and external pressure in various thermodynamic systems.
Students and professionals in physics and engineering, particularly those focusing on thermodynamics and fluid mechanics, will benefit from this discussion.