Recent content by Worzo

OK, I should have probably checked my figures before I said that. Albedo Earth = 0.36, Albedo Moon = 0.07.

That's what I thought, but I can't find any expression for how the viscosity changes at low pressure.

The reason this is possible (as Dr T says, the optical branch has non-zero energy at k=0) is because k is not really a wavenumber. p = [hbar]k is the 'crystal momentum', which is not a real momentum.

Need some more detail. How long is the rail? What is the field strength of the cobalt magnet? How quickly do you want to accelerate the cobalt magnet? What is the 'travel length' of the magnet? Indeed, what is the point of constructing this?

Take out the horizontal motion of the horse - assume that the forces on its legs as a result of this are the same whether it is jumping or not. So the problem is reduced to simply a horse falling onto its front two legs, since the vertical motion of the horse has stopped by the time the rear...

I believe heat from the Earth's core is negligible compared to solar radiation. I'm not going to check your figures, but I expect the Moon would be colder due to its higher albedo i.e. the Moon reflects more sunlight than the Earth, and thus is not as hot.

Firstly, this isn't my homework question. I was trying to answer another, broader question for a student, and it boiled down to this one. There's quite a subtle point here, I think, but I just can't grasp it. Consider stable atmospheric conditions on Mars and Earth. A feather is dropped from...

It's only true that these two neutrons in the bound state have to have an antisymmetric TOTAL wavefunction. I thought it would be analagous to two electrons with the same spatial wavefunction, but opposite spins.

I'm talking about the fact that it is apparently impossible write down the wavefunction for two bound neutrons because it is zero, and this has something to do with the reason on this page, but I don't understand it: http://www.madsci.org/posts/archives/sep99/938380774.Ph.r.html

How did you work this out?

Hello, Can someone explain to me exactly why a bound state of two identical nucleons is not possible? I have a feeling its something to do with antisymmetric wavefunction, but haven't found a satisfactory explanation in any book. Cheers.

Uh oh...don't start that one off!

For the first part of working out the potential, you have to employ the TDSE, this is true. However, you should recognise that this is the wavefunction for a free particle, in the form: [psi] = Aexp[i(kx - wt)], where A = normalisation factor, p=[hbar]k, E = [hbar]w. Hence in this example, p...

OK, the analogy was a bad one for that reason. It's not helpful to think of a bound electron (as in an atom) as a particle. There is a wavefunction describing the probability of finding the electron in a certain place, if you wanted to look. It's this probability distribution that oscillates...

Quantum mechanics shows that the electron does not "jump" once from one energy level to another: the wavefunction has a time-varying probability of being in the first energy level and the second energy level. This probabiltiy oscillates between the two levels whilst gradually moving from one...