Weight of Hot Body: Balance in Thermal Equilibrium?

  • Context: Graduate 
  • Thread starter Thread starter bernhard.rothenstein
  • Start date Start date
  • Tags Tags
    Body Hot Weight
Click For Summary
SUMMARY

The discussion centers on the mechanical and thermal equilibrium of a spherical hot body with temperature T, placed on a sensitive balance. When the temperature of the hot body equals the ambient temperature, the balance does not maintain mechanical equilibrium, as established by arguments presented in the paper at arxiv.org. The conversation also touches on the implications of the general theory of relativity, specifically regarding kinetic energy's contribution to gravitational mass, and the lack of literature discussing observational evidence for this prediction. Carlip's formula for gravitational mass is referenced, linking it to the Komar mass formula applicable to static metrics.

PREREQUISITES
  • Understanding of thermal and mechanical equilibrium concepts
  • Familiarity with general relativity and its implications on mass
  • Knowledge of Carlip's formula for gravitational mass
  • Basic grasp of kinetic energy's role in gravitational mass
NEXT STEPS
  • Research the implications of the equivalence principle in general relativity
  • Study Carlip's formula and its applications in gravitational physics
  • Examine the experimental data testing kinetic energy's contribution to gravitational mass
  • Explore the Komar mass formula and its relevance to static metrics
USEFUL FOR

Physicists, researchers in gravitational theory, and students studying general relativity will benefit from this discussion, particularly those interested in the interplay between thermal and mechanical equilibrium in physical systems.

bernhard.rothenstein
Messages
988
Reaction score
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.
 
Physics news on Phys.org
The balance does not remain in a state of mechanical equilibrium - this follows from argments presented in

http://arxiv.org/abs/gr-qc/9909014

According to the general theory of relativity, kinetic energy contributes to gravitational mass. Surprisingly, the observational evidence for this prediction does not seem to be discussed in the literature. I reanalyze existing experimental data to test the equivalence principle for the kinetic energy of atomic electrons, and show that fairly strong limits on possible violations can be obtained.

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.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 19 ·
Replies
19
Views
2K
Replies
8
Views
2K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 26 ·
Replies
26
Views
3K
  • · Replies 24 ·
Replies
24
Views
2K
  • · Replies 20 ·
Replies
20
Views
4K
  • · Replies 2 ·
Replies
2
Views
3K