Recent content by lerus

I was talking about formula for gammas. But I need to think a bit more before asking questions. Thank you.

Thank you. You described better than I could describe myself. And, yes , you are right I still need this formulae for covariant derivative $$A_{\alpha\beta;\gamma} = A_{\alpha\beta,\gamma} - A_{\alpha\sigma}\Gamma^{\sigma\beta\gamma} - A_{\beta\sigma}\Gamma^{\sigma\alpha\gamma}$$ I also need the...

Thank you for your answer. We can repeat this for any point, isn't it enough?

Thank you for your answer, I actually used LaTeX and in preview everything looked OK, but when I posted, something happened. Sorry... Did I understand correctly that that this formulae ##A_{\alpha \beta ; \gamma} = A_{\alpha \beta , \gamma} - A_{\sigma \alpha }\Gamma^{\sigma}_{\beta \gamma} -...

I'm reading "Problem Book In Relativity and Gravitation". In this book there is a problem 7.5 Show that metric tensor is covariant constant. To prove it, authors suggest to use formulae for covariant derivative: Aαβ;γ=Aαβ,γ−AσαΓβγσ−AσβΓαγσ after that they write this formulae for tensor g and...

Thank you, very interesting article. It is possible to argue with some of the statements made there, but still very interesting. Thank you.

Thanks a lot for example, I think I understand it better now If variables ##x, y, z## were independent then ## \left( \frac {\partial w} {\partial x} \right)_y \equiv \left( \frac {\partial w} {\partial x} \right) _z## but if ##x, y, z## are not independent, then ## \left( \frac {\partial w}...

Thank you for reply. For instance, we have function ## V \left( T, P, X \right) ## When we calculate ## \left( \frac {\partial V} {\partial T} \right) ## we change ##T## and keep ##P## and ##X## constant When we calculate ## \left( \frac {\partial V} {\partial T} \right)_P ## we do the same...

Thank you for your reply For instance, if we have function ## V \left( T, P, X \right) ## is ## \left( \frac {\partial V} {\partial T} \right)_P \equiv \left( \frac {\partial V} {\partial T} \right) ## Thank you.

I just started to study thermodynamics and very often I see formulas like this: $$ \left( \frac {\partial V} {\partial T} \right)_P $$ explanation of this formula is something similar to: partial derivative of ##V## with respect to ##T## while ##P## is constant. But as far as I remember...

Thank you for the links. I saw similar results in other places but it is difficult to understand how it is possible that one observer observes radiation when another doesn't. Radiation takes energy and momentum - it means if charge radiates then it will not follow geodesics. But if there is...

Thanks a lot, somehow I didn't find it myself. But is it possible that for in free falling observer particle doesn't radiate but for supported observer radiation exists? I think I have to read the article.

From one point of view the charged particle is accelerating and should emit electromagnetic waves. But from the equivalence principle, I think, it should not. Does anybody know the answer?

You don't need to rotate anything - Earth rotates for you

In this experiment light moves only in 1 direction - from Jovian moons to the Earth - that's why this is a true one-way measure of speed of light. We don't need to synchronize any clock here, but to interpret results of this experiment we do need to assume that space is isotropic. But on the...