Understanding Entropy and Free Falling Objects in a Vacuum System

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Discussion Overview

The discussion centers on the concept of entropy in the context of a free-falling object in a vacuum system. Participants explore whether entropy changes during the fall and the implications of reversible processes in this scenario.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question whether entropy changes when an object falls without air resistance, suggesting that if ΔS=0, the process is reversible.
  • Others propose that it is impossible for the object to return to its original height without energy loss, raising the question of how entropy could increase during the fall.
  • There is a suggestion that if ΔS=0 indicates reversibility, then the object should be able to rise again, leading to the assertion that ΔS must be greater than 0.
  • One participant mentions that the object could rise after a perfect elastic collision or through a frictionless ramp, implying conditions under which the process could be considered reversible.

Areas of Agreement / Disagreement

Participants express differing views on whether entropy increases during the fall and the implications of reversibility, indicating that multiple competing views remain without consensus.

Contextual Notes

Participants assume ideal conditions such as no air resistance and no energy loss, but these assumptions are not universally accepted or resolved within the discussion.

kimpantip
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Dear sir,

Hi, Everyone. I have a question about entropy. If the object falls without air resistant (vacuum system) , Is entropy changed? If ΔS=0, it means reversible, is it possible that the object can go back to the original height? I know that it is impossible but can we explain that ΔS >0.
Within the condition as following:
*** Focus on within the space (free falling under gravity)

Thank you very much
 
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If the object falls without air resistant (vacuum system) , Is entropy changed? If ΔS=0, it means reversible, is it possible that the object can go back to the original height?
What do you think?

I know that it is impossible
Why? Assuming there are no other mechanisms where energy gets lost (inelastic collisions for example).
 
What do you think?

Why? Assuming there are no other mechanisms where energy gets lost (inelastic collisions for example).


The thing that I wonder is how can entropy increase while the object is falling in spite of no air resistant and no collision on the ground.
 
That's my question: why do you think it would increase?
 
why do you think it would increase?

ifΔs=0 it reversible, object is able to rise! so i think that Δs>0
 
kimpantip said:
ifΔs=0 it reversible, object is able to rise!
Sure it is, and it will do so after a perfect elastic collision (or a frictionless U-shaped ramp).
 

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