Recent content by dulrich

Here's something... Frequency of a pendulum = \frac{1}{2\pi}\sqrt{\frac{g}{L}} So, the length of your pendulum will be about 3.6 microns. The decibel level depends on your distance. The logic would be Intensity level => intensity => power => energy => amplitude So this could tell...

This is probably asking about gravitational red-shift. Remember that light coming out of a gravitational well appears red-shifted -- light falling into the same gravitational well will appear blue-shifted. Mach's principle is the conjecture that the inertia of objects is related to mass of the...

What does the net charge have to do with it? A moving charge will experience a force in a magnetic field via F = qv x B. The current is just a lot of negative charges moving, so the current should feel the same force. The positive charges are stationary, so there is no counter-balancing magnetic...

Two observers will agree on whether the particles are at the same position at the same time. The relativity of simultaneity has to do with whether events separated in space are simultaneous or not.

Hmm. I'm almost sure I don't understand the question, because it's too easy. I've been recently reviewing my thermodynamics and that's one of the reasons I was interested in this thread. So I am certainly willing to read more. But isn't a standard example like mixing ice and water in a...

Energy is conserved, entropy is not. The entropy of a system increases until its energy distribution reaches equilibrium. Perhaps you are thinking of some application of non-equilibrium thermodynamics of which I am not aware (very possible), but that's the textbook answer.

The potential energy of a charge is the product of its charge and the electric potential in which it sits: PE = qV. Since the charge of an electron is negative, if the electric potential around it is negative, the potential energy will be positive. If another negative charge is around, its...

Well, that's an open ended question! Maxwell's laws describe the dynamics of the electromagnetic field, i.e., how the field changes with time in response to the motion of charges. All electrical, magnetic and optical phenomena are fundamentally described by these four equations (in...

There is no such thing as beyond infinity. Truly, there is no such thing as having the electron at infinity either. It's just a short-hand way of saying suppose you separate the electron far, far away without limit.

Try N = mg/cos θ... :wink:

Matricies are cleaner and if you have the time to figure it out, that is the preferable way to go. However, this "brute-force" way will work. The best part is that if you keep clean notes, simply plug your answers back in and you will know for sure if you have the right answer regardless how you...

I think DrDu answered this in post #78 (for an infinitesimally small cube). The diagonal elements are the components of the force normal to the surface in question (i.e., F_x = \epsilon_{xx} n_x), while the off-diagonal elements are the components perpendicular to the surface (i.e., F_y =...

I see. Thanks for the clarification.

Thanks for sharing that experience. I'll see what else I can dig up on the method.

I was trying to address this statement in post #62: But as I said, I didn't really understand your point. I appreciate this, quite a bit actually. I don't want to hijack the thread (although that's already been accomplished :smile:), but can you expand on this statement or point me to somewhere...