Recent content by magicfountain

Hey, thanks for the quick reply. That's a pretty satisfying answer. Much appreciated! So it's pure coincidence that the EOM of F don't have A in them, I guess.

In my lecture we were discussing the Lagrangian construction of Electromagnetism. We built it from the vector potential ##A^\mu##. We introduced the field tensor ##F^{\mu \nu}##. We could write the Langrangian in a very short fashion as ##-\frac{1}{4}F_{\mu \nu}F^{\mu \nu}## In the end we...

@mpv_plate awesome :O thanks!

I need to put some Feynman Diagrams in a paper that I'm writing on my Mac (Lion) with Texpad, but I don't know how to create them in Latex (I tried it with some things I found on google [feynmf], but it didn't work). So I need a way to create them online, if you know one. I hope this is the...

Homework Statement Oil and water are put in a cylindrical container. They can rotate at various frequency around the rotational symmetry axis. Consider gravitational and radial forces to find the form of the surface between the fluids. no friction, no mixing the surface has the form of a...

thank you! now it seems obvious. :D

Homework Statement I'm trying to find the function, that describes the velocity approaching to a terminal velocity.Homework Equations F_{net}=mg-\frac{1}{2}\rho v^2 AC_dThe Attempt at a Solution F=ma a=F/m \dot{v}=F/m=g-\frac{1}{2m}\rho v^2 AC_d \dot{v}=g-kv^2 \dot{v}+kv^2=g (k and g are...

just in case you need some visualization I've as far as to see, that my current approach also contradicts the observation that the fluids will go to the walls of the container for faster rotations. This leads me to thinking that i will definitely have to work in the centripetal force...

Homework Statement In a cylindrical container (with radius R) there are 2 fluids (separated like water and oil, fluid 1 lies under fluid 2) with given volumes V_i, given densities ρ_i. You let them rotate with respective angular frequencies ω_i. There is no friction. Find the functions of...

thanks very much jambaugh although the idea of assuming "there is an entropy for each object which is a function of the amount of internal randomized energy. S = S(E) and that this entropy is a somewhat additive measure of how randomized a system is." seems tough to swallow, your explanation...

i thought this was the definition of entropy. how do you assign a numerical value to S (or how do you define it) then?

dE=T*dS I don't understand this equation. Does anybody care to show me why that holds?

@bcrowell @Bill_K that helped a lot. i guessed that i had to do lagrange multipliers with relativistic expressions, but i was too lazy to really think about it. thanks for reminding me that it actually just leads to the partition function and you have to plug in the rel. terms there.

In thermodynamics (ignoring relativistic effects) you can use the maxwell-boltzmann-distribution to find the average speed of the gas particles. v^2=\frac{8kT}{\pi m} But there are high Temperatures that would have average speeds > c. Are there distributions that describe gases with an...

Very helpful. Thanks!