Recent content by komodekork

In thermodynamics one of the maxwell relations is: \left( \frac{\partial S}{\partial V} \right)_T = \left( \frac{\partial P}{\partial T} \right)_V When I try to derive it from dU = TdS - PdV i get: T = \left( \frac{\partial U}{\partial S} \right)_V P = -\left( \frac{\partial...

Ok, I don't get a cycloid, but this kind of curve. Does it look resonable? edit. I guess that's what's called an extended cycloid?

Maybe I should have made this more explicit. I'm talking about what would a circle with radius r in a frame S look like, in a frame S', who is the instantaneous rest frame of a particle moving on that circle in frame S. Does that make sense? I guess my question is what would the transformation...

So if I were to transform the coordinates of all the points on the circle in the laboratory frame by the Lorentz transformation to the rest frame of the electron, then they would all coincide with the origin of that frame?

So a electron moves in a circle with radius r in a magnetic field. What does that circle look like in the rest frame of the electron?

When physicist talk about time after the big bang, what do they mean? Time is relative, so which frame of reference are they talking about? Could anyone please explain?

But forget all of that, just in a genreal case, if H=H( \dot{q},q) is it constant just because it's not H=H(p,q,t)? Or because it cancels out?

I don't know what my Hamilton represents. I may have done something wrong. I all i got is this lagrangian L = \frac{m}{2} (\dot{q}^2 sin^2(\omega t) + \dot{q} q \omega sin(2\omega t) + \omega^2 q^2) and this new coordinate Q = q sin(\omega t) after this substitution i get L =...

Hm... I don't know if I see what you are getting at. I'm not sure if you are telling me that what you did is right or wrong. Should it be \frac{d}{dt}(H) = m ( \dot{Q} \ddot{Q} - \omega^2 Q \dot{Q} ) or just \frac{d}{dt}(H) = 0

I don't understand what you mean, could you please explain?

Lets say H = \frac{m}{2} (\dot{Q}^2 - \omega^2 Q^2 ) where Q is the generalized coordinate. It doesn't explicitly depend on time, but the Q and the \dot{Q} does. If i differentiate it with respect to time it should be zero if it's constant, right? So i guess my question is should i treat the Q's...

I see. How dense would the radiation in the spheres need to be to account for the dark matter? Ridiculously high? Because the radius of the spheres seems to be 12500 lightyears.

Yes, I did read the article. I don't know much about dark matter, but as i understand it, the evidence for dark matter is that that the velocity curve of the galaxy falls off much slower than we expect with just the mass we see. So this is a new, never before seen gigantic structure in the...

http://www.nasa.gov/images/content/498884main_DF3_Fermi_bubble_art_labels.jpg http://www.nasa.gov/mission_pages/GLAST/news/new-structure.html Could these structures account for the dark matter, or is the density profile inconsistent with two big blobs of matter/energy on both sides of the...

Ofcourse, but that's not what I am asking about. I'm asking why treat time differently? Is there some reasoning other than "we do it because it works". In eucledian geometry one would just add everything, but in Lorentz geometry there is this minus. I guess my question is, how/why did Lorentz...