# Tag Info

### Physical meaning of each term of the square modulus of a wave function

1 - The cross term $\psi_0\psi_1\cos(\omega t)$ can be interpreted as an interference term of the states $\psi_0$ and $\psi_0$, which importantly depends on time, as these states have different ...

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### What does $v$ actually represent in pulley problems?

By your definition that $v=dl/dt$, $v$ is just the rate of change in the lengths of the rope segments supporting their respective masses. Here you define $v$ to be a scalar, since $l$ is also a scalar,...
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### Question regarding gravitational force as external force

My doubt is if gravitational force is considered as an external force Yes, it is considered as an external force, an external conservative force. ...so how come can we apply Total mechanical energy ...
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### Issue with simplifying the equation related to non-uniform acceleration

The equation $$\frac {d v}{dt}= A+ B\, v^2$$ with constant $A$ and $B$ is an example of a Riccati equation. The Wikipedi article shows you how to solve it.
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### For an objective falling, reaching terminal velocity and then hitting the ground, how can I find the force it exerts on the ground?

Short answer: The given information is not enough. Long answer: You correctly noted that the force of the impact is related to the change in momentum. We take off from there. If we assume the duration ...
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### Doubts in circuit analysis

Maybe I am loosing some detail here, but assuming that all resistances are equal, and looking at the symmetry of the circuit, all dpps and currents should be the same in module if you flip the circuit ...
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### Buoyancy basics

Divide the world into 3 parts. 1) The ice cube, 2) the fluid, and 3) enough fluid to fill the hole if the ice cube was not there. If you only had 1) or 3), they would fall down because of their weight....
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### 1D Lattice with site dependent magnetic field

I would say the result is just a statement about the structure of the phase/configuration space, which is spherical with no preferred direction(s) in the case of a magnetic moment. The partition ...
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### A capacitor partially filled with dielectric

For some background, let's remind ourselves that the electric field is a conservative field. Because of this, we can define potentials that are independent of the particular path of integration. So ...
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### Rotating a system

As for what most people mean when they say rotate the axis - yes, it usually implies keeping all objects in the same points in space, and just using new coordinates to express their position, velocity ...
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### I need to find the state of the system at a general time, knowing the Hamiltonian and the state at $t=0$

The Hamiltonian for a certain three-level system is represented by the matrix $$H = \begin{pmatrix}a & 0 & b \\ 0 & c & 0 \\ b & 0 & a\end{pmatrix},$$ where $a$, $b$, and $c$ ...
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