Does Air Entering an Evacuated Bottle Perform Work?

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SUMMARY

When air enters an evacuated bottle upon opening the cork, work is indeed performed by the air. This work occurs due to the acceleration of the air and the overcoming of drag in the neck of the bottle. The discussion clarifies that while the textbook states work is done, it raises questions about the applicability of the equation W=∫PdV, which is typically associated with quasi-equilibrium processes. Therefore, the scenario involves both dynamic and static considerations of work.

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  • Understanding of thermodynamics principles, particularly work and energy.
  • Familiarity with the concept of free expansion in gas dynamics.
  • Knowledge of quasi-equilibrium processes in thermodynamic systems.
  • Basic understanding of fluid dynamics, especially regarding drag forces.
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Students and professionals in physics, particularly those studying thermodynamics and fluid dynamics, as well as educators looking to clarify concepts related to work done by gases in dynamic systems.

kini.Amith
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When air enters into an evacuated bottle from atmosphere when the cork is opened, is there any work done by the air? My textbook says that there is , but i thought no work was done during free expansion?
Consider the amount of air entering as the system.
Moreover, is W=∫PdV applicable only for quasi eqbm process or all processes?
 
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Some work is done in accelerating the air and in overcoming drag in the neck of the bottle. But whether that's what the textbook author had in mind I've no idea.
 

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