It's consistent define position of a particle in some frame as a vector or is just a Physics informality? Velocity and Acceleration can be added up and bring multiplied by real numbers an have physical meaning ( they live in tangent spaces). But what's the physical meaning of adding a position t...

I have read this question: https://physics.stackexchange.com/a/462620/132371 where John Rennie says: When the two particles become entangled the means the total wavefunction Ψ can no longer be separated into an A part and a B part, so we can no longer write down an equation like equation (1...

Setup Consider the following situation: Two (small) balls hang by two identical ideal threads, such that in their initial states the threads are perfectly vertical. The two balls are moved by small, equal angles, $\theta_0$ (while keeping the threads under tension), and then released from rest. ...

How do you describe the energy of a certain system in quantum field theory?

I encountered a Physics Olympiad problem: A ball bearing rests on a ramp fixed to the top of a car which is accelerating horizontally. The position of the ball bearing relative to the ramp is used as a measure of the acceleration of the car. Show that if the acceleration is to be proportional to...

This is something anyone could easily verify. When we open a tap slowly, water bends inwards (towards the axis) while maintaining its laminar flow. After a certain height below the opening, the flow becomes turbulent. I've approximately illustrated the shape of water near the top portion in the f...