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seen Apr 8 at 7:26

May
1
asked A conceptual problem with Euler-Bernoulli beam theory and Euler buckling
Apr
2
comment Power laws and deterministic systems
This is a totally different question. The answer, in short, is that a deterministic system can be described deterministically. Very often, however, you can't do that because the system has too many degrees of freedom (e.g. sand-piles) so that a full deterministic solution is both infeasible and useless. In such cases, a probabilistic description usually casts more light on what is going on.
Apr
1
comment Deriving the Lagrangian for a free particle
I think the best advice one can give you is don't read Landau & Lifshitz. They are great books for reference, but practically impossible to learn from. If you're into analytical mechanics then Goldstein is a good place to start, or Arnold, if you're more interested in the mathematical aspects.
Mar
29
comment Is there analysis library for stress-strain data?
In that case, send my your credit card number and I'll do it for 500$!
Mar
29
comment Is there analysis library for stress-strain data?
I don't know of any software, but at least for the Young's modulus, yield stress and work it will be very easy. I doubt that you can get the fracture toughness from these data.
Mar
21
comment Calculating Ground State Energy in 1D Potential
This is exactly the point. As the particle is large, it is localized. The localization will be around the minimum of the potential. Could you write up a solution and post it, answering your own question?
Mar
19
comment How many photons does it take to measure a linear polarization?
What do you know about the measuring device? If it is perfect then you can get an exact result (as many bits as you like) with two measurements.
Mar
19
awarded  Citizen Patrol
Mar
15
awarded  Necromancer
Mar
8
comment Find drag force on link of rotating chain
If the link is infinitely small, then the force will also be infinitely small. I think what you're looking for is force density
Mar
5
comment Why are scattering matrices unitary?
related:physics.stackexchange.com/q/18539
Mar
5
comment Why do steam bubbles increase in size as they rise?
Why did you turn down the simpler explanation - that as the bubbles rise the surrounding pressure decreases, and they simply expand ($V=\frac{Nk_bT}{P}$) without transfer of mass or energy?
Feb
20
comment Force from point charge on perfect dipole
The general formula for the force is, as you correctly stated $F=q\Delta E$, which is conveniently written in a geometrical form as the dot product $$\vec F=\vec\nabla\vec E \cdot q\Delta\vec r =\vec \nabla\vec E \cdot\vec P$$ Note that $\vec\nabla\vec E$ is a matrix. However, when you work in any other coordinate system, the gradient $\vec \nabla$ is no longer the simple expressions that you are used to. You can derive the formula for it by differentiating the expression $$\vec E=E_r\hat r+E_\phi \hat \phi+E_\theta\hat\theta$$ and remembering that the unit vectors are also space-dependent.
Feb
18
comment Showing constraint is nonholonomic
You can explicitly build an example that shows that these constraints are not path-independent.
Feb
16
comment Connection between momentum and energy
Answer: the question is ill-posed.
Feb
14
comment How to write classical dynamics of solids in tensor form (relation of stiffness and viscosity tensor)?
Each time you're making it worse! You want to do fracture? God forbid. References about fracture of amorphous solids: here and here and here and here.
Feb
14
comment How to write classical dynamics of solids in tensor form (relation of stiffness and viscosity tensor)?
Note that whenever irreversible deformation occurs, $\epsilon_{ij}$ is not even defined any more, as the reference configuration changes. So this whole approach of developing $$\sigma_{ij}=C_{ijkl}\epsilon_{ij}+\partial_t(\dots\epsilon_{ij})+\dots$$ is basically invalid. It seems, though, that what you're looking for is standard isotropic visco-elasticity. So grab the textbook I recommended and read the first few chapters. It's fairly easy.
Feb
13
answered Why can't we ascribe a (possibly velocity dependent) potential to a dissipative force?
Feb
12
awarded  Organizer
Feb
12
revised How to write classical dynamics of solids in tensor form (relation of stiffness and viscosity tensor)?
edited tags