Recent content by JoAuSc

Roughly speaking, the temperature depends on the average energy of the molecules, not the average speed, so there would be no upper limit.

I see why you were puzzled. Could you elaborate? Does this assume that each electron exists in a definite energy rather than a superposition of different Bloch waves?

Forget the models. I mentioned the infinite square well model as an example of a model where electrons are delocalized, but that doesn't mean I'm wedded to it. I used it to show people my basis for believing that electrons were spread across the solid. For that purpose, I assumed the ISW model...

Thank you, I think you've provided the best answer so far. I'll look into what you said to Manchot about the relationship between quantum mechanics and the Boltzmann equation. Ditto. Perhaps it would be clearer if I asked a couple of related questions: How can we reconcile the image of...

You're arguing that for bulk solids, it physically doesn't matter whether you choose the infinite square well's sine waves or the free particle models's complex exponentials, but that using the latter is much simpler to deal with. I'll concede that, though only the ISW has a non-zero fermi...

It does make sense that the liquid would cause more stress on the middle of the cup's bottom than at a point near the rim, even if the force is the same in both places. The stresses should be radially symmetric while in either position. I'm guessing, though, that the bottom probably contorts to...

Thank you, everyone. I didn't expect to go to physicsforums and find a month-old thread of mine with 15 replies. I don't doubt that an infinite square well is a bad approximation for a solid, missing behaviors such as band gaps and such, but it seems like a good way to discuss whether...

I think you have to use quantum mechanics to get a rigorous reason for not getting a contribution for rotations about the axis of a diatomic molecule. Classically, even a diatomic molecule with a very small (non-zero) moment of inertia about its axis would contribute the same amount to the...

I feel like I'm missing information. What's "2V" referring to? Is there a power source in this circuit? Do we charge the capacitor, then add it to the circuit after it's charged?

You are saying a force on a mass exists if and only if there is an acceleration (in your terms, if "it opposes the motion"). This is Newton's First Law. It doesn't make sense to "apply a force on a force". Instead, we should say "apply a force to an object causing that force". As Pengwuino said...

Let's start with an easier example: one resistor and one battery connected to the circuit by a switch. We turn on the switch. Now, we learn in class that there is a voltage increase across the battery and a voltage decrease across the circuit, and that in general, when you sum the voltage...

Here's what happens when you rub two objects together: 1. You add kinetic energy to the object by rubbing the objects together, striking them together, etc. The atoms in the object gain kinetic energy. Soon enough this internal kinetic energy reaches thermal equilibrium. If you dropped the...

When you rub two objects together and generate heat from the friction, the energy comes from you, and is transformed into vibrational/heat energy in the object. You can't cool an object by rubbing it. Is this what you meant?

How much do you know already?

"More energetic particles" means "particles with a higher momentum". It's similar to things orbiting around the sun. If an object has a velocity that's too high, it'll leave the solar system and never return, but if the velocity's not too high, it'll just orbit around the sun in an ellipse, or...