If we could fly away from the Earth (imagine Superman), at what point would we notice the Earth's spin (or at what point would be stop moving along with the Earth)? Or is that just not how relativity works, if not please do explain how.

Pauli's Exclusion principle states 2 fermions can not occupy the same quantum state. However, a particle can occupy a superposition of quantum states. Does this mean you can have an infinite amount of particles occupying a slightly different superposition of states? Where the superposition of sta...

A tensor is formally defined as an object whose components obey some transformation rules. I, however, find it more intuitive to look at (second-order) tensors as a linear operator/function between two vectors. Thus the stress tensor $\sigma$ connects the surface normal $\vec{n}$ to the force act...

I understand that, in curvilinear coordinates, one can define a covariant basis and a contravariant basis. It seems to me that any vector can be decomposed in either of those basis, thus one can have covariant components and contravariant components of the same vector, depending on the chosen bas...

I am trying to derive the equations of motion for a complex scalar field given by: $$L = \partial_\mu \phi^* \partial^\mu \phi - m^2 \phi^*\phi$$ Euler-Lagrange equation: $$\partial_\mu \frac{\delta L}{\delta(\partial_\mu \phi)}-\frac{\delta L}{\delta\phi} = 0.$$ From $\delta L / \delta\p...

Q) An insect crawls up a hemispherical surface very slowly.The coeffiecient of friction is $\mu$ between surface and insect.If line joining the centre of hemispherical surface to the insect makes an angle $\alpha $ with the vertical, find the maximum possible value of $\alpha$. With the f...

In my special relativity course we defined 4-momentum P as mU where U is the 4-velocity. Then by definition P is a 4-vector. We then defined E via $E/c = P^0$ and claimed that E is a conserved energy quantity based on the first 2 terms of its Taylor expansion. This was presented as being a not-c...

In the book Quantum Field Theory for the Gifted Amateur, the author stated that, having a field that transforms locally via $\psi(x) \rightarrow \psi(x)e^{i \alpha(x)}$ will destroy local symmetry -and he is right- but he said we can fix that right up by adding a field $A_\mu(x)$ and replacing de...