# Tag Info

### Potential energy of a particle inside a magnetic vector potential

The vector potential represents potential momentum. As the hamiltonian contains the square of the momentum an interaction term proportional to $\vec p \cdot \vec A$ results.
1 vote

### Potential energy of a particle inside a magnetic vector potential

To call this quantity the potential energy is misleading. When a particle is subject to an external (non-dynamical) field we can define a potential energy $U$ for the particle if doing so gives a ...
1 vote

### How to calculate the potential energy of a large object as an integral?

If you take a horizontal slice of the cone of at height $x$ width depth $\delta x$ then this has volume $\pi r(x)^2 \delta x$ where $r(x)$ is the radius of the cone at height $x$ (assuming a solid ...

### Method of image charges for electric potential in a metallic disk

Check out Jackson's Classical Electrodynamics section 3.12 "Mixed Boundary Conditions; Charged Conducting Disc." The method is actually the reverse of the method of images. Usually, the ...
1 vote
Accepted

### Confusion in definition of Potential Energy

Without writing the explicit meaning of formulae, comments, and answers may only increase the original confusion. The work done by a force ${\bf F}$ when a point-like body is displaced along any path ...

### Confusion in definition of Potential Energy

Your definition of potential energy is wrong. Yes, $ΔPE_{AB}=-W_{AB}$, but $W_{AB}$ is not the work done by the conservative force from $A$ to $B$. It is the work done by an external force (against ...

### Dimensionless value to differentiate between concretated and dispersed mass systems

This is by no means a complete answer (or any, maybe), but I'd like to point out that your center-of-mass approach has some disadvantages. If I understand correctly, your suggestion is to take the ...

1 vote

### Charged Particle in Magnetic Field

For a charged particle in circular motion in a magnetic field, it is not instructive to think in terms of energy conservation: the speed of the particle is a constant, so the kinetic energy \$(1/2)\,m|\...

### Gravitational Potential Energy irony

It is because the work done here considered is external work and gravity is pulling towards earth while we are applying approximately same force opposing it to cause opposite displacement that bring ...

### Source of magnetic dipole potential energy

But since magnetic field has non-zero curl, how can such magnetic potential energy be interpreted? And what is the source of that energy since magnetic field does no work? Magnetic field is not, in ...
Accepted

### Conservative force and change in the mechanical energy

Conservative forces can cause changes in kinetic energy. For example, the conservative force of gravity doing work on a falling object gives that object kinetic energy. It's just that conservative ...

### Physics of every-day life: rotating bag of tea

There is an important fact about the rotating tea bag that is not addressed. Why does it speed up before it eventually stops? Answer: This is an important example of the Law of Conservation of Angular ...
1 vote
Accepted

### With regard to Mechanical Energy what forms of Potential energy are included?

I've seen the mechanical energy of a system defined as the sum of its kinetic and potential energies. What forms of potential energy are included in this definition? Gravitational and elastic ...