Recent content by Hank_Rearden

Homework Statement "The gravitational constant G is 6.67*10^-11 m^3*s^-2*kg^-1. What is G in units of cm^3*s^2*g^-1 Homework Equations 1kg = 1000g 1m = 100cm The Attempt at a Solution I don't understand how the dimension can change from [L^3,T^-2,M^-1] to [L^3,T^2,M^-1]...

Homework Statement You are standing 2.5m directly in front of one of two loudspeakers. they are 3m apart and both are playing a 686hz tone in phase. As you begin to walk directly away from the speaker, at what distances from the speaker do you hear a minimum sound intensity? Assume speed of...

Quick question, that seems pretty obvious, but I wanted to check. Magnetic fields follow the rules of super-position similar to the way electric fields do, correct?

That makes sense, thanks

I've seen it used before, and I think I understand it as a concept, but I'm not particularly adept at using it myself

Integrate from 0 to a, (C*r)*(2*pi*r) dr?

but where is the expression dA/dR coming from?

I've been using \pi*r^{2} dr as my dA

Sorry, I'm not ignoring you, I'm just still getting the hang of using PF's symbols

Homework Statement A long, solid, conducting cylindrical wire of radius a has a current density J(r) = Cr and carries a total current I find a value for the constant C in terms of I and a Homework Equations J = I/A The Attempt at a Solution I believe that I need to...

Well, what types of lights are used in things like commercially available laser tag systems that won't cause eye damage?

Can anyone recommend a good laser diode that won't cause damage to the eye with prolonged exposure?

Can anyone tell me what the most standard way of changing the frequency of an AC power supply is? Can it be done with circuitry or does the method of generation need to be set at the desired frequency?

It's because by increasing the voltage, you're decreasing the current in the wires, which means the volume of electrons scraping against the side of the wire also decreases, so less energy is lost over long distances.

Yeah that seems like it's more your mind's interpretation of time, no human can travel anywhere near fast enough to notice time dilation.