If the universe were moving as a whole ( say we are a pocket universe and got dropped along the way with momentum from the parent universe's expansion ) then how would that affect the universal speed limit? Or would it not because it's an internal speed limit? What I'm getting at is that if you...

How can we prove a statement, "at any point in Electromagnetic field energy density stored in magnetic field is equal to energy density stored in magnetic field?

Can you nuke Jupiter by sending an atomic bomb well protected by submarine capable of withstanding high pressure, enter layer of superfluid hydrogen and then ignite it?

When one is exactly at the critical angle, the light behaves in a way that may be interpreted as "something in between" refraction and reflection: it continues in a direction that is tangent to the boundary of the mediums. When the angle is smaller than the critical angle, we get refraction. A...

How to show that the area $A$ of the region $$\{(x,y)\in\mathbb R^2 : |x|\le y\le e^{-x^2}\}$$ is such that $$0 < A = 2\int_{0}^{\beta}{(e^{-t^2}-t)dt} < 1$$ in which $\beta>0$ satisfies $e^{-\beta^2}=\beta$

In school, we learn that $T = Fd$, where $T$ is the torque, $F$ is the force perpendicular to the moment arm, and $d$ is the length of the moment arm. If I was the first physicist to come up with this model for torque, what might my train of thought be? In other words, how does one come up with t...

If potential V= 2x+5 . What would happen to elecron coming from positive x axis? I think it should speed up as the potential is postive. Am i right?

Why is force = mass $\times$ acceleration? I have searched in many sites but didn't actually get at it. Simply I want to know that if a mass in space moves (gains velocity thus further accelerates), how can I think, postulate and further believe that force = multiplication of mass and its accele...

I'm trying to understand Noether's theorem, and it's application to gauge symmetry. Below what I've done so far. First, the global gauge symmetry. I'm starting with the Lagragian $$L_{1}=\partial^{\mu}\Psi\partial_{\mu}\Psi^{\ast}-m^{2}\left|\Psi\right|^{2}$$ with classical complex fields. Th...

It's intuitively clear that the energy most accurately describes how much the state of the system is changing with time. So if the laws of physics don't depend on time, then the amount how much the state of the system changes with time has to be conserved because it's still changing in the same w...