Charge density of a disk with radius a in cylindrical coordinates
To write the uniform charge density of a disk with radius a in cylindrical coordinates, If we do this form: [itex]\rho (x)=\frac{A\delta(z)\Theta (a-\rho)}{\rho}[/itex] (A is constant that sholud be...
View ArticleDiffusion: Concentration profile for point sink in infinite plane
Hello, I have a certain diffusion problem I am trying to solve. Admittedly, I'm further behind on my math than I'd like, and have trouble setting it up properly, and no luck finding an exact analogue...
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Colliding Ovals
Hi, I Have set up 4 collisions between two Ovals (AA,BB,CC,DD) and I would like to know if the outcome will be identical for all 4 of them. First of, when looking at this orange collision that is going...
View ArticleIs the efficiency of heat engine more in hilly areas than in plains?
In hilly areas temp is low than plain areas.So the temperature of source as well as sink must be low.But ratio remains same.So efficiency is same as in plain areas? Is my logic correct? Or anything...
View ArticleBody trajectory and force direction
Hello Forum, Let's consider a particle that is giving an initial speed in a certain direction. The particle is now moving in that initial direction at a constant speed. If a later moment a force starts...
View ArticleSingle minded Foucault pendulum
I have completed a bottom driven pendulum that seems to have a preference to swing E/W. It is a 10kg bob on a 6M wire. The pivot is a tungsten carbide pin resting on a watch jewel. No matter how I...
View ArticleAbsorption and emission power
Three bodies 1,2,3 are in closed region. Region is at temperature ##T##. ##e_{\lambda,T}## - spectral emission power ##a_{\lambda,T}## - spectral absorption power In experiment...
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what is program used in ray tracing simulation?
what is program used as attached.thank you! Attached Images ray.png (154.7 KB)
View ArticleTrouble with self-energy formula
Hi everyone, I'm having a little difficulty trying to calculate the self-energy of a uniformly charged sphere of radius a. That is, the work done in assembling such a distribution of charge. It is to...
View ArticleIR and UV absorption of materials
Hello all, I am looking for easy to obtain materials, preferably in powder form, with good absorbance at 808nm, 365 nm and 404 nm each (either one material for each wavelength or one for all...
View ArticleSpring Gun
I have a question about a spring gun. Suppose the barrel of a spring gun is placed horizontally at the edge of a horizontal table. You put say a marble in the barrel and compress the spring x cm and...
View ArticleEnergy -- need a proper definition please
Please could someone give me a proper definition of energy. My teacher said in class today that "there is no such thing as different types of energy". He said that although we learn this in...
View ArticleClassical treatment of statistical mechanics
I've been reading, in my own time, a first course in thermodynamics and they present a quantum treatment of statistical mechanics (discrete energy levels), but on the article for the partition function...
View ArticleHemholtz free energy proof
http://en.wikipedia.org/wiki/Helmhol...ium_Conditions Hi. In the proof that dw <= -dA for isothermal work, where is it assumed T must be constant during the whole process?
View ArticleHow to differentiate by a vector ?
Is it possible to differentiate a scalar( in this case a Lagrangian) by a vector ? If the Lagrangian is r.A ie. the scalar product of vectors r and A what is ∂L/∂r ? My notes say it is A but how ? My...
View Articlesome questions about dielectrics/insulators
Dielectrics are insulating materials that can be polarized in the presence of an external E-field, so are all insulators with the ability to distribute its charges throughout its volume considered...
View ArticlePhase velocity faster than light?
I am currently taking an undergrads course in atomic physics, and I have just grazed the concepts of matter wave functions, group waves, group velocity, and phase velocity. For the latter, it has been...
View Article"Dumping" Entropy
Hello everyone, I am reading Daniel Schroeder's Thermal Physics book. One phrase he uses that I find particular confusing is that a system has to "dump" entropy. As one example, in chapter 5 he briefly...
View Articlemetamaterial in supersonic
Could we use something like carpet cloaking to reduce shockwave in supersonic or mach wave in transonic flight? Student in mechanical engineering
View Articlecapacitors don't require a "dielectric" material they?
whenever i hear about capacitors, i hear about the 'dielectric' material, but a dielectric material as opposed to a non-dielectric insulator just means that the material is polarizable. but...
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