Recent content by passingthru

That 'imbicilie' was P.A.M. Dirac. Name-calling is very stupid.

The superscript o after the subshell indicates odd parity. When the parity is even, there is no superscript. I hesitate to venture further, because it's a little fuzzy to me as well. I think that the odd parity results if you get a negative value when summing spins, like if you have a total...

Can you look up the polar form of the equation for an ellipse, in terms of r, $\theta$, and the eccentricity? Can you find the angle, given the components of the velocity?

Forgive me if this has already been discussed. I've been searching and haven't found it. When summing the spin of an atom in the Russell-Saunders coupling scheme, some texts include the spin of an odd nucleon, and some don't. For example, if an atomic energy state is described as ${3}^P_{2}$...

A study of particle physics reveals that electrons have internal structure, if I understand it correctly, and that's a big if, three quarks. I don't know anything about how the quarks are coupled inside the electron. The classical concept of angular momentum of a rotating bead is the simplest...

Given the components of the velocity, can you determine the angle at that point? What is the polar equation for an ellipse in terms of the eccentricity?

In the OP, when you say "process" do you mean only reversible ones?

I appreciate your help, both AM and SC. I'm rereading my thermo text. It says basically the same thing, that dQ = TdS only when in equilibrium. I'm still wondering how to arrive at ETS's answer with dQ= dW = 0. I know that dS is an exact differential, and so is dV. If we wait until the system...

The OP does not state what the contents of the system are or whether or not those contents do any work. I do not understand free expansion. For example, question 47 in the GRE Physics bulletin describes the volume being doubled by removing a divider where one side initially contains an ideal...

Your problem doesn't state how the volume was increased, whether it was done by the gas, or by opening a divider of some sort. . The first law for non-diffusive systems is $d U = d Q -d W$. In this problem, $d U = 0$ so that $d Q = d W = T d S = P dV$. From the ideal gas law, $PV = nRT$. Using...

To be specific, my real question is this: since the first derivative squared and the second derivative are generally not equal, why is it that we assert in undergrad phys that mechanical work done on a particle is equal to the kinetic energy gained? Work = $\int \frac{d\; \vec{p}}{dt} \bullet d...

When you say that no work is being done because the plane is not moving, what you are really saying is that no NET work is being done which is not the same as no work at all being done. It's like saying that if the net force on it is zero, then there are no forces at all. This is not the case...

The key fact here is that power is being used to maintain the plane in a stationary position, suggesting that the plane will move or fall without the power. What happens quantitatively if you suddenly stop supplying the power. The plane falls at a certain rate depending on the force of gravity...

I think that by "not generally true" it was just meant to suggest that there is a more general expression which always holds which does not depend on qualifying statements, like requiring that the acceleration be constant or that the force be constant, for example. When a discussion begins with...

I have more elementary questions about pair production. Why does it have to be near a large nucleus. I've read that it's because of relativity and some observer may see a reduced frequency of the photon because of the relativistic doppler effect. Why does a large nulceus fix that problem? Is it...