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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
Feb
12
answered How to write classical dynamics of solids in tensor form (relation of stiffness and viscosity tensor)?
Feb
10
comment Abstract, generic derivations of energy
You put the "Hamiltonian-mechanics" tag, so you know the answer. If your equations of motion are derived from an Hamiltonian, then the Hamiltonian can be considered as an "energy",
Feb
5
comment Symmetries of separable potential
I don't think the notation you use is standard. What are these symmetries? What does "separable" mean?
Feb
2
revised Is there symmetry in 2d stress tensor in linear elastic fracture mechanics?
typos
Feb
2
answered Does the Banach-Tarski paradox contradict our understanding of nature?