Questions tagged [equilibrium]
Equilibrium is the condition of a system in which all competing influences are balanced. These can range from forces (static/dynamic equilibrium), to chemical processes (chemical equilibrium) and temperature gradients (thermal equilibrium).
119
questions
82
votes
7
answers
11k
views
Why is the Earth so fat?
I made a naive calculation of the height of Earth's equatorial bulge and found that it should be about 10km. The true height is about 20km. My question is: why is there this discrepancy?
The ...
- 53.2k
9
votes
3
answers
4k
views
Why are thermodynamic potentials minimised?
Why is it that, at equilibrium, certain potentials are minimised?
That is, for a system at constant temperature and pressure, the Gibbs free energy is minimised, and for fixed volume and temperature, ...
- 1,933
43
votes
8
answers
6k
views
Prove that negative absolute temperatures are actually hotter than positive absolute temperatures
Could someone provide me with a mathematical proof of why, a system with an absolute negative Kelvin temperature (such that of a spin system) is hotter than any system with a positive temperature (in ...
user7757
8
votes
2
answers
801
views
Assumptions of thermodynamic & chemical equilibrium in fluid-dynamics
I am reading about the Euler equations of fluid dynamics from
Leveque's Numerical Methods for Conservation Laws. After introducing the mass, momentum and energy equations, some thermodynamic concepts ...
- 501
7
votes
2
answers
2k
views
How are the Lagrange points determined?
According to Hyper Physics, there are 5 equilibrium, or Lagrange points of the Earth-Moon system and only 2 of them are said to represent stable equilibrium points.
This made me think if there is an ...
user171347
23
votes
6
answers
4k
views
Is thermodynamics only applicable to systems in equilibrium?
So I was going through callen's thermodynamics book and their he says that thermodynamics is only applicable to systems which are in equilibrium and that naturally raised a few questions in my mind
...
- 543
9
votes
4
answers
2k
views
What maximizes entropy? [duplicate]
Liouville theorem states that the phase space distribution function of a system remains unchanged with the system evolution,
$$
\frac{\text{d}\rho}{\text{d}t}=\frac{\partial \rho}{\partial t}+\sum_{i=...
- 60.3k
17
votes
14
answers
17k
views
Why do rain drops fall with a constant velocity?
While reading my physics book. I came across a line that says that:
Rain drop falls with a constant velocity because the weight(which is the force of gravity acting on body) of the drop is balanced ...
user315348
25
votes
4
answers
32k
views
Why does the nature always prefer low energy and maximum entropy?
Why does the nature always prefer low energy and maximum entropy?
I've just learned electrostatics and I still have no idea why like charges repel each other.
http://in.answers.yahoo.com/question/...
- 253
2
votes
1
answer
6k
views
Estimate the reaction force on each leg of a 4-legged table
Assume you have a table with four legs with a weight placed somewhere inside the boundary created by the legs. The task is to determine the reaction force at each leg. Here are the problem ...
- 23
13
votes
5
answers
1k
views
Adiabatic piston: why is Callen's argument flawed?
This question is related to this one. I would ask you to read that question and my answer to the question itself before answering this one.
The problem is the following. In his book Thermodynamics, ...
- 16.4k
7
votes
1
answer
2k
views
What's the point with equilibrium in thermodynamics?
All the thermodynamics books I saw until now state that in thermodynamics we are mainly concerned with equilibrium states (I know there's "non-equilibrium thermodynamics", but I'm interested ...
- 36.4k
7
votes
5
answers
631
views
Slow thermal equilibrium
I have a question which is inspired by considering the light field coming off an incandescent lightbulb. As a blackbody radiation field, the light is in thermal equilibrium at temperature $T$, which ...
- 134k
5
votes
1
answer
3k
views
Definitions in thermodynamics: temperature, thermal equilibrium, heat
I'm currently reading Fermi's "Thermodynamics" and I'm trying to grasp the (possibly different) right definitions for temperature,
thermal equilibrium, heat.
To clarify, I'm looking for definitions ...
- 4,654
0
votes
4
answers
309
views
Why isn't this rod in neutral equilibrium?
Suppose that the rod shown below in figure(1) is balanced. So the torque about point $O$ is $Mg.x-mg.y=0$.
[figure(1)]
Then imagine than M is lifted a little bit up making an angle of $\theta$ with ...
- 2,578