Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Weight of a hot body

  1. Mar 21, 2006 #1
    Consider a spherical hot body having a temperature T, located on one of the pans of a very sensitive balance. It is equilibrated puting a given mass on the other pan of the balance. The temperature T is lower then the ambiental one. The balance is in mechanical equilibrium but out of thermal equilibrium. Does the balance remain in a state of mechanical equilibrium when its temperature equates the ambiental one? The transmission of energy is isotropic.
  2. jcsd
  3. Mar 21, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    The balance does not remain in a state of mechanical equilibrium - this follows from argments presented in


    It's also been discussed a lot here on the board, you can probably find the past discussions if you look.

    Carlip's formula for "gravitational mass", the intergal of density + 3*pressure, is basically the flat-space version of the more general Komar mass formula which applies to any static metric.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Weight of a hot body
  1. Mass of a body (Replies: 41)

  2. Relative weight (Replies: 4)

  3. A Moving Body (Replies: 14)

  4. The weight of flywheel (Replies: 11)