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Resonant frequency of this pendulum?
Hi everyone, I'm planning a simple experiment for my school, which involves fixing a mass M onto a rod of length L made of a copper alloy. Suppose I drive it capacitively, how do I find the resonant...
View ArticleGauss's Theorem
gauss's theorem is also applicable to charge in motion.but how the surface integral has to be taken??
View ArticleElectromagnetic induction
Hello everyone, One very basic thing about this phenomenon is not very clear to me. If a conductor moves in a region of uniform magnetic field, would it have an EMF induced across it? I'm confused...
View ArticleLandau-Lifshitz Navier-Stokes equation on which page of the textbook?
I see some papers mentioning the fluctuating hydrodynamics, which originates from the Landau-Lifshitz Navier-Stokes (LLNS) equation. I know that the LLNS equation has added a thermal fluctuation term...
View ArticleDiving Board question help
A diver steps off a platform at 7.5m above a 4.97 deep pool what is the minimum constant acceleration in the water so the diver wont hit the bottom
View ArticleContinuity equation derivation in Griffiths - why partial derivative?
Greetings, In Griffiths E&M, 3rd. Ed., on page 214, the following is part of the derivation of the continuity equation (the same derivation is shown on the Wikipedia article for the current...
View ArticleUniqueness of the solution with certain boundary conditions
Hey! Speaking electrodynamics, I can't seem to get mathematically or even physically convinced that the solution with Dirichlet or Neumann boundary conditions is UNIQUE. Can someone explain it? Thanks.
View ArticleA water fountain that seems to defy gravity
I saw a strange thing on antiques roadshow that I can't figure out. It was a small water fountain made of glass and metal that appears to make water go uphill. It is totally manual but I don't...
View ArticlePartition function for position-independent hamiltonian
Hi everyone. Suppose I have an Hamiltonian which doesn't depend on the position (think for example to the free-particle one [itex]H=p^2/2m[/itex]). I know that the classical partition function for the...
View ArticleTrying to recall an old experiment
I have searched on google but cannot find this old physics experiment. It is most probably due to my failing memory and not choosing the right search terms I am hoping someone can recall the...
View ArticleGears optimum relation
Hi all, i have a doubt. How much teeth in relationship to his radius need to have a gear to be optimal? And, if i have 2 gears with same radius and same #of teeth, to have low friction and low negative...
View ArticleRetarded Potential and Energy
Hi All, I've been reading Griffiths E&M and Feynman Lectures (vol 2, E&M), and it made me think about a gedanken that I'm trying to resolve. I'm pretty sure once I really peruse the chapters on...
View ArticleSuperconductor: Magnetic Field Strength VS distance
Hi all, Does anyone know how the magnetic field strength of a superconductor varies as distance from the outside of the superconductor? Aside from a superconductor being able to creates a stronger...
View Article2nd grade homework concerns
My daughter came home with this assignment (see PDF link below) tonight. Am I right to be concerned when they equate power with force, and size with mass? Or am I just over-blowing this for 2nd grade?...
View ArticleMagnetic field from a coil (on Mathematica)
Hello guys, I'm trying to find the configuration of two circular coils in a configuration similar to Helmholtz coils that would homogenize the magnetic field best at a volume between them. So the first...
View ArticleHeat of reaction
Hi! In most textbooks on chemical physics/thermodymanics it is said that under fixed pressure the heat of reaction equals change of enthalpy of the system since [itex]dU = \delta Q - p\cdot dV[/itex],...
View ArticleSpeed Pertaining to Circular Motion
Hi, So v=ω*r Where v = velocity in m/s ω = angular velocity in rad/s r = radius in m But I am confused...the units don't match! What happens to the rad? m/s = (rad/s)*s My textbook doesn't explain it,...
View ArticleDo electrons only "feel" the electric field?
Imagine that you're an electron. You are always at rest in your inertial frame so that you do not "feel" the [itex]\mathbf{v} \times \mathbf{B}[/itex] term of the Lorentz force. Thus, from your...
View Articlefinding launch angel from velocities
I'm having troubling finding a launch angel from a set of given velocities. v=2[itex]\hat{i}[/itex], 4[itex]\hat{j}[/itex] at t=0 v=2[itex]\hat{i}[/itex], 2[itex]\hat{j}[/itex] at t=1...
View ArticleInverse Square Law
Quoting from Wiki, bolded section mine: Quote: Because of the inverse-square law in radio communications, the digital data rates used in the downlinks from the Voyagers has been continually decreasing...
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