I'm researching on transformers and curious to know about what this shape is called (the actual core block, ignore the wires around it).

I want to look at the complex wave function $\psi$ in quantum mechanics. If a complex number $a + bi$ is multiplied by $i$ it is rotated by 90 degree in the complex plane. What does this mean for a complex scalar field, i.e. the wave function $\psi$? I know, that $i\psi$ is as well a solution of ...

I am not a physicist, but I know the first law of thermodynamic (conversation of energy), and I have connected this with an idea that came to my mind some time ago to create perpetual motion machine which impossible according to the first law of thermodynamic. This spinning wheel is made of ferr...

I was playing table tennis the other day when I my ball fell off the table. I placed my paddle above it in order to slow it down, and then I brought the paddle to the ground so that the ball would come to a stop. A diagram of what I did is below: Why did the velocity of the ping pong ball increa...

I am wondering if there are any natural phenomenon that cannot be explained by classical mechanics when we live in everyday life but can be explained only by quantum mechanics. By classical mechanics, I mean Newtonian mechanics and Maxwell's electromagnetic theory. I know the macro scale quantum ...

If we say that the $|\psi\rangle$ is in the Hilbert space what does the space of density matrix? Is this phrase true? $|\psi\rangle \langle\psi| \in V \otimes V_\mathrm{dual}$ $V$ is vector space.