Recent content by diagopod

Thanks for helping me out here Simon, and I see your point. At the same time, it does seem, at least in normal circumstances, that anything that operates on X is by definition an operator with respect to X. A concrete example might be a hammer driving a nail into the wall. Of course, one could...

Thanks, that certainly gives me some direction. Thanks Simon. To explore the point a bit further, suppose you took one wave packet (A), for example, and had it interfere with another wavepacket (B), resulting in a new packet or state. In this context, would wave packet A be functioning as an...

I've found the wave-packet picture quite useful as I work my way through the very basics of quantum mechanics. But I'm having trouble finding a wave-mechanical picture of operators. For example, at least in terms of a free particle, using the wave mechanics treatment (as opposed to the matrix...

Thanks sophiecentaur. Your description of the Van der Graaff as half of a capacitor, the other half being the Earth, is illuminating, and gives me a lot to ponder. Thanks again.

Thanks Antiphon. Thanks kmarinas86. I'll have a look at electrets. Overall, I'm starting to get the sense that there are few cases in which very high concentrations of net charge are stored. Van De Graaff generators, for example, seem to store a surprisingly small amount of charge, yet discharge...

Trying to learn the basics of capacitors, but I'm hung up on a conceptual issue. It seems that capacitors must be charged up, generally with the help of a current from outside the capacitor, such as a flow of electrons that pile up on one of the plates. So in that sense, the capacitor must be...

Good point. So suppose one takes a simpler case, where compression would not seem to result in additional mass-energy. Suppose, for example, one had a spherical cluster of relatively motionless asteroids, each with a rest mass of 10^5kg, and each 10 meters on average from its surrounding...

Thanks. Just to make sure I follow you, are you saying that if Observer A is the same distance from two bodies B and C, both with the same rest mass, but with C having twice the density of B, Observer A will experience the same attractive "force" to B and C? Or will A experience a greater...

I've been trying to get a sense of the differences b/w Newtonian gravity and GR. One thing I was curious about. I'm reasonably certain that Newtonian gravity predicts that two objects of the same mass, but different densities, exert the same gravitational force on a given object at distance R...

Thanks. Would you say it's also arbitrary the direction of the electric field, as in the direction of the arrows we see in field lines diverging from positive charges and converging on negative ones, or is that different?

Thanks, yeah, the bit about positive and negative current has always thrown me - absolute value to the rescue :)

that makes perfect sense, thanks for the clarification alxm

Learning about the nature of current, the Ampere and its role in Epsilon0. I'm assuming that the fact that the Ampere is defined in terms of electrons per second is arbitrary and that it could just as well have been protons per second? And if it had been protons per second, then Epsilon0 would...

Nope, but thanks for the link. It looks like that particular poster seems to think that G can be derived. I'm aware that G is an empirical constant. What I was curious about was whether there was a more fundamental (albeit still empirical) constant inside of G that had the same relation to G...

I'm trying to learn more about the differences and similarities b/w electrostatics and gravitation. Ke and G seem structurally similar, but while Ke can be broken down into 1 / 4 pi Epsilon0, I was wondering if there is a similar sub-structure for G? Is there any unit in gravitation analogous to...