Say a regular string, with mass, is held by two persons in each end and they are in running in different acceleration in the same direction. Will there be any tension as different ends have different acceleration? Or not as they running in the same direction? If it does then how do you calculate ...

I believe Ohm's law via the drude model (about average collisions time). Right after, I read about internal resistance of a battery, and they used Ohm's law as a justification. That doesn't make sense though; in a battery the current flows (in the battery) from MINUS to PLUS, which means Ohm's la...

I wish to compute $$[\nabla_{\mu}, \nabla_{\nu}]e^{\lambda}_{~~a}. $$ To do so, I make use of $\nabla_{\nu}e^{\lambda}_{~~a} = \omega_{a~~~\nu}^{~~b}e^{\lambda}_{~~b}$, so that I may write $$\nabla_{\mu}\nabla_{\nu}e^{\lambda}_{~~~a} = \nabla_{\mu}(\omega_{a~~~\nu}^{~~~b})e^{\lambda}_{~~b}+\omega...

If a force of 10N is applied to different objects of different mass in empty space, in the absence of gravity, why lighter objects accelerate faster than heavier objects, why mass causes inertia.

We use the speed of light to define the length of the meter, but we also use the speed of light to count the number of clicks on our clocks (because all the electromagnetic events on the smallest subatomic level known interfere with the speed of light). So we have space = $f(c)$ and time = $g(c)$...

In section 2.4 of the book, it seems that the commutation relation $[\pi(x,t),\phi(x',t)\nabla^2\phi(x',t)] = 2[\pi(x,t),\phi(x',t)]\nabla^2\phi$ is used to verify that $i\frac{\partial}{\partial t}\pi(x,t)=-i(-\nabla^2+m^2)\phi(x,t)$ and show that the Klein-Gordon equation holds in the Heisenber...

I would like to understand what exactly happens when Landau damping takes place. I have seen the mathematics of it. But I am not sure If I truly understand what happens when we are talking about Landau damping.