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Magnet Phenomenon: The "divergent" region of a ring magnet
Here's a puzzler: I have a NdFeB ring magnet, 1.75" outer diameter x 1.375" inner diameter x 0.25" thick, N40 grade. It is axially magnetized so that the north pole is toward one face and the south...
View ArticleDerivation of Potential Energy for Multi-Particle Systems
I am reading 'Classical Dynamics: A Contemporary Approach' by J. Jose, and I am confused about a step in the author's development of potential energy for a system of many particles. He begins by...
View ArticleMagnetic component of light, natural materials vs metamaterials
Why is it that the magnetic component of light interacts more with metamaterials than with naturally occurring materials? It would be nice to explain this in terms of inductance, permeability, and...
View ArticleHow to remove sprung mass pitch motion due to input surface?
Hello All, I have measured acceleration data from the sprung mass of vehicle, travelling at (almost) constant speed. There are sufficient accelerometers, to allow the sprung mass angular acceleration,...
View ArticleDeriving the local field and Clausius Mossotti formula in a dielectric
(My last http://www.physicsforums.com/showthr...10#post4424810 post did not get much attention so I try again without all these formulae. Think this will be more clear...) To derive the local field in...
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Capacitance approximation of a non parallel plate capacitor
I am in process of designing a homemade capacitance sensor and I'd like to have an approximation of the resulting capacitance of the following geometry. The plates are placed on the outer surface of a...
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Idea 2 for how to break the second law of thermodynamics
Hello! I have another idea for how to break the second law of thermodynamics, and I don't see where this one cracks either. I would be glad if someone could explain this to me. Kelvin-Planck statement...
View ArticleWhat exactly happens when the area is reduced? (forces & pressure)
From what I've learnt, the pressure increases when the area is reduced. Taking the high heels as an example, the tip of high heels have a really small surface area which result in high pressure. But,...
View ArticleMapping Rotations of Relative Axes to Fixed Axes
So I have been trying to figure out some orientation data that I gather from a triaxial gyroscope, and figure out my orientation using only initial conditions and angular velocity from the gyroscope's...
View ArticleInductance
"when we apply AC to an inductor (pure inductance), the current will lag the applied voltage by 90 degrees. " how this happens? why current lags applied voltage by 90 degrees? :confused:
View ArticleMagnetic field energy conceptual question
Hello, I have some trouble understanding an expression for the magnetic field energy .There are basically two different general expressions: a)[itex]\int(\int_0^B\vec{H}.\delta{\vec{B}}) d^3r[/itex]...
View ArticleHow does temperature vary with height from floor to ceiling?
We all know the air at the ceiling is warmer than the air at the floor because "hot air rises" due to the density gradient. But I started wondering how drastic is this effect actually? Noticeable, at...
View ArticleGraduate Classical Mechanics Problem Book
My graduate course (2 sem) follows Goldstein (All chapters :surprised). Can anyone suggest me a book with solved problems on such advanced topics?
View ArticleDissolved air in the water
Air can be dissolved in water. I read some information that the dissolved air exists in the form of molecule, for example, oxygen can be dissolved in the water, and the fish can get dissolved oxygen...
View ArticleBlackbody radiation - Radiative flux derivation of the Stefan-Boltz.
I am trying to resolve some long standing problems I have encountered with blackbody radiation. Namely, the derivation of the radiation energy flux equation $$J=\sigma_{B} T^4$$. I understand the...
View Article[Difficult] Gas Dynamics Situation
Hoping someone finds this problem interesting, I'm looking for some ideas on how to solve a real world problem, not a complete and detailed solution. This topic is related to an astrophysical...
View ArticleWhy doesn't light interfere in a room?
I was asked this question and couldn't think of a good answer. In a room there's infinite different light waves going in every possible direction. How can we possible see anything at all? If I put a...
View ArticleBifilar Pendulum in real life situation
If someone is walking across the log (rod) of a bifilar pendulum, how would the period of oscillations be affected if the pendulum is oscillating horizontally (other than the length of the suspension...
View Articlequestion on derivation of potential of a small current loop
The vector magnetic potential is given [tex]\vec A=\frac{\mu I}{4\pi}\oint\frac{e^{-j\beta R_1}}{R_1}dl'[/tex] After a few steps, the equation becomes: [tex]\vec A=\frac{\mu I}{4\pi}e^{-j \beta...
View ArticleConditions for Cherenkov Radiation
As far as I know, Cherenkov radiation occurs when a charged particle travels through a medium at a greater phase velocity than the speed of light in that medium. Molecules in that medium are polarized...
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