Recent content by Zarquon

OK, thanks, I get it now. What threw me off whas the fact that I can't decide what the input impedances are, since these will depend on the load; but of course I can make sure that they are greater than 100 kΩ regardless of load.

OK, maybe I get it now.. The input impedance of a voltage source is the impedance 'seen' by that source? So it's not a property of the source itself? In that case I am still confused about this problem I'm supposed to solve (this should maybe go in the homework section, though): "A...

I am familiar with the concept of the internal resistance of a voltage source, but what is meant by the input impedance?

Thanks. Part of the reason for my confusion is this page: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/helmholtz.html Seems to me that the "work to give the system final volume V at constant pressure p" should be equal to pV where p is the pressure from the surroundings?

In the expression defining Gibbs free energy, G = U - TS +pV, are T and p the temperature and pressure of the environment, or of the system itself? Or is it a requirement that the system has the same temperature and pressure as the environment for the Gibbs free energy to be defined?

But is there an explicit requirement on ΔLx and ΔLy? I still don't get it.

Yes, but how about a simultaneous eigenfunction for the operators L^2 and Lz, such that Lz = 0 and L^2 != 0. In this case Ly and Lx must be uncertain(?), so I'm wondering if there's some relation that sets a limit for how precisely these can be determined.

Right, good point.. Thanks! OK, but what is the minimum requirement on the uncertainties of Lx and Ly in this case (I mean if we measure Lz = 0, L^2 != 0). Seems like there should be one?

Right. But I still have a problem with this: If either of the components is exactly zero, say L_z = 0; then we get the relations (ΔLx)(ΔLy) >= 0 (ΔLy)(ΔLz) >= h\2*E(Lx) and so on. My problem is the second inequality, when ΔLz = 0.

But those other relations involve (ΔL_x)*(ΔL_z) and (ΔL_y)*(ΔL_z)? What if ΔL_z = 0?

Alright, it's beginning to make sense to me now. Thanks a lot, guys!

Thanks, that clarifies things a bit! But now I'm a bit confused with the equipartition principle: according to what I've been told, a degree of freedom is the same as an independent variable that contributes an amount to the energy proportional to its square, and each degree of freedom...

It seems to me that there should only be three degrees of freedom for each atom in a crystal, one for each direction of vibration; but apparently there are six? Can someone explain? Thanks.

An infinitely long "mass-spring transmission line", consisting of masses (m) connected by springs (spring constant s) obeys the following dispersion relation: ω = \sqrt{4s/m} sin(kd/2). The group velocity is dω/dk = d/2 \sqrt{4s/m} cos(kd/2). What does zero group velocity "mean" for...

Not sure if we're talking about the same "analysis" here. I was just trying to explain what happens to the object when released from the rocket.