Recent content by sspitz

Oh, by the way, I would just like thank you for replying. I had pretty much given up.

Inside the conducting box the E field is zero. At least I know this for sure when the box is empty, so I assume if the test charge is small enough, it won't have an effect on the distribution of charge on the conductor. If the test charge is large enough that it does have an effect, I don't...

Why does a metal sheet between two wires not have a shielding effect on the magnetic field? Considering the magnetic force can be explained as the electric field in a different frame. With wires changing frames is a little complicated, but take this simplified situation. In the lab frame...

A point mass has a force on it in its rest frame (F). Now go to a frame moving in the +x direction (F'). EM book claims the forces can be related like this: f'_{x'}=f_{x}\\f'_{y'}=\frac{f_{y}}{\gamma}\\f'_{z'}=\frac{f_{z}}{\gamma} I would like to be able to see this with four vectors...

End of a book on mechanics. The next chapter is more formal. I would just like an intuitive grasp of what the rest mass is and how to set up simple conservation law equations such as in compton scattering.

My book says that if two objects collide completely inelastically, the rest mass of the composite is greater than the sum. I assume this happens because the objects heat up and this is counted in their energy. However, in other problems the book assumes the rest mass of objects/particles is...

Well, you definitely can't ignore B because it must affect the distribution of charge on the conductor. Maybe you can prove the new distribution still exerts no force on B. I find it bizarre that ch. 3 of an intro EM book would have this problem and no explanation. I have no rigorous...

Alas, no. It is definitely a charge of arbitrary Q for both A and B. I think in the specific example, A is at the center of a spherical cavity, but not centered in the conductor. Not sure if that matters and why or why not.

Suppose there is a cavity inside a conductor. Outside the conductor there is a point charge (A). E inside the cavity is zero because the field from the conductor and point charge cancel. That I believe. Suppose I add a point charge (B) inside the cavity. Obviously, there is a radial...

Thanks for the help. Sorry about not defining the problem first. I was thinking about it so long that I forgot to put it in context. I'll just stick to your definitions. I'm not sure I completely understand your full argument. Is is basically this: For E>V, applying the boundary...

A particle of energy E is incident from the left on a potential step. If the energy of the particle is greater than the height of the step, it is acceptable to discard: Fe^{-ikx} saying that there is nothing incident from the right. If E is less than the step, it is not acceptable to...

Thanks for the help. I think I got it. As a check on comprehension, I'd be interested in knowing if #2 in the original post is right or wrong and why. It seems to me that phi(k) above is for energy eigenfunctions what the momentum space wavefunction is for momentum eigenfunctions. That is...

Homework Statement Check the energy-time uncertainty principle for: \Psi(x,0)=Ae^{-ax^2}e^{ilx} using the observable x. Homework Equations \Delta{E}\Delta{t}\geq\hbar/2\\ \Delta{E}=\sigma_H=\sqrt{<H^2>-<H>^2}\\ \Delta{t}=\frac{\sigma_x}{\frac{d<x>}{dt}} The Attempt at a...

Thanks for replying amal. I was hoping we could look a little more specifically at the examples. #1: I'm not sure I understand your analysis of the system. My understanding is that the correct solution is that block 1 enters with velocity v. AFter the collision, block 1 stops moving, and...

I've managed to really confuse myself on the conservation of energy in a system. I guess the basic question boils down to why is the total mechanical energy of a system a meaningful quantity. I understand E for a point particle in a conservative field is constant. I understand E for CoM...