Principle of minimum energy
Confuses me. In which case is it the helmholtz free energy, the gibbs free energy, the energy that gets minimized and why? Also is it consistent with energy conservation and how is that possible if you...
View ArticleAlan Guth thought experiment about negative energy and gravity
Recently, I watched a lecture with Alan Guth. He made an interesting statement. He said that to create an electric field requires work, because the like-charges prefer to repel one another, therefore...
View ArticleWhat causes an electron to flow in a current?
Say I have a copper wire connecting the earth and the moon (or some other large distance). The Earth side is touching a "negative" source and the moon is about to touch a positive one". As soon as the...
View ArticleCoupled motions
Hello there, A weather ballon is released, and its acceleration in the z-x-plane, a is governed by a buoyancy force, B, which is constant in the k-direction. gravitational acceleration, 9.81 m/s^2, in...
View ArticleSuction force and pressure difference
I am doing a study to see whether suction force can act as a mechanism to compress air. Lets say I have a normal syringe, which consist of the small cylindrical tip at the top of syringes where you...
View Articlenavier stokes question
hey pf! so when deriving navier stokes we have, from newton's second law, [itex]\sum \vec{F} = m\frac{d \vec{V}}{dt}[/itex] when deriving the full navier stokes (constant density) the acceleration term...
View ArticleConducting loop suspended in a magnetic field
Consider a conducting loop with resistance R and area A suspended by a non-conducting wire in a magnetic field [itex] \vec{B}=B\hat{y} [/itex]. The wire is a torsion spring with constant k.The...
View ArticleClassical explanation of double slit polarization experiment
I have a disagreement with a Quantum mechanical scientist about a double slit experiment with polarizers, which gives interference or not depending on "which path" knowledge of the photon. That is...
View ArticleLagrangian density of Newtonian gravity
Hi everyone! I've been thinking about a certain problem for a while now. And that is a Lagrangian formulation of Newtonian gravity. I know there is a Lagrangian formulation for general relativity. But...
View ArticleWhy does Quantum yield need to be constant to determe Abs x-sec
Hi, For finding absorption crosssection, why is it necessary that that the quantum yield of the fluorescence be constant for all the wavelengths in the absorption spectrum? Using F = Abs X-section x I...
View ArticleConfused about gravitational potential energy?
There is several things I am confused about with gravitational potential energy. So, first of all, shouldn't U=mgh always be written ΔU=mgΔh, because isn't that equation only dealing with differences...
View ArticleWhy does ITC measure Enthalpy, not Gibbs Energy?
Isothermal Titration Calorimetry measures the enthalpy of (e.g.) protein binding by measuring the amount of heat that must be added/removed to a solution in order to perfectly balance the heat...
View ArticleIs any iron a good core?
B = μ0nI Usually, the value of B is quite small... I'd like to boost the magnetic field B to a much larger and stronger field, and the most efficient way I find to do that is using a high permeability...
View ArticleNo change in wavelength of a monochromatic light
I searched for the images of refraction on google images and i saw an image where a laser light was incident on a regular glass slab. Bending of light was clearly seen in the picture. According to...
View ArticleEntropy, chemical potential, temperature
For a thermodynamic system there exists a function called entropy S(U,N,V) etc. We then define for instance temperature as: 1/T = ∂S/∂U μ = ∂S/∂N etc. When taking these partial it is understood that we...
View Articleclassical atom
I know there are other things that fail about the rutherford atom but as the electron is accelerating and radiating away energy it would fall into the nucleus, my question is how much energy would the...
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[Thermodynamics] Is this even possible?
I'm not asking about the specific questions contained in the attached document - I know all the answers. I'm wondering if this is even possible. A to B: free expansion (which I take always means...
View ArticleDistance from non-uniform linear acceleration
I have an object at rest which accelerates at a variable rate before coming to rest again. At any given point I can determine it's linear acceleration, accounted for gravity. I would like to determine...
View ArticleBuilding up some intuition with Gauss's LAw
I'm trying to build up some intuition with Gauss's law, calculating the flux through surfaces given certain charge configurations etc. For example, for any number of different charges enclosed in a box...
View ArticleQuestions about kinetic energy and momentum
Hi, I am currently in High School physics and we are going over Energy and Momentum. I have some questions about how and why they both work. *all objects are assumed to have the same mass Since...
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