1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Entropy falling objects

  1. Sep 20, 2013 #1
    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
    Sincerely,
     
  2. jcsd
  3. Sep 20, 2013 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    What do you think?

    Why? Assuming there are no other mechanisms where energy gets lost (inelastic collisions for example).
     
  4. Sep 20, 2013 #3

    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.
     
  5. Sep 20, 2013 #4

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    That's my question: why do you think it would increase?
     
  6. Sep 20, 2013 #5
    ifΔs=0 it reversible, object is able to rise!!!! so i think that Δs>0
     
  7. Sep 20, 2013 #6

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Sure it is, and it will do so after a perfect elastic collision (or a frictionless U-shaped ramp).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Entropy falling objects
  1. A falling object (Replies: 12)

Loading...