Recent content by StephenD420

Hello all, I have a quick question regarding the relation of the space-time metric and the curvature. I have determined the space-time metric, g_(alpha beta), but I am unsure as how to go from the line element ds^2 = [ 1 + (dz/dr)^2] dr^2 + r^2 dtheta^2 and the space-time metric g to the...

Hello all, I am a senior physics undergraduate student. I have wondered about the Taylor Expansion for a few years now and just have never bothered to ask. But I will now: I know the Taylor Expansion goes like: f(a) + \frac{f'(a)}{1!}*(x-a) + \frac{f''(a)}{2!}*(x-a)^{2} +...

bump... Am I correct in my thinking about the electron radius? Thanks, Stephen

Hello all I have a quick question regarding the derivation of the radius of an electron using the compton wavelength. Is the following true? λ = h/mc where 2*pi*r = λ from quantum angular momentum L = mvr = h/2pi -> mcr = h/2pi -> 2pi*r = h/mc = λ ?? so r = h/(2*pi*m*c) ? I just want to make...

Using the equations from http://blog.makezine.com/2010/06/28/make-your-own-gears/ I found that using 40 teeth for the sun gear, 18 teeth for the planet gears and 80 teeth for the ring gear gives the following outer diameter values in inches using a diametrical pitch of 8.835729338 sun gear...

But I have read that the number of teeth in the ring gear has to equal R = 2P + S where P is the number of teeth in the planet gears and S is the number of teeth of the sun gear. Is this not true? And yes the gears are circular just my drawing skills in paint leaves much to be desired. Stephen

Hello all: I have a quick question concerning a variation of a planetary gear train I am working on. If I want a sun gear and then two planetary gears in between the sun and ring gear (like is shown in the attached picture), how do I find the number of teeth for the ring gear? Would the...

Hello all I have a quick concept question concerning electrical current. For real life components, would they only draw the current needed...In other words, if the current of a voltage source of 12V happened to be 500A going through a resistor of 2 ohms, would the resistor pull only 6A or...

ahhh of course! thanks.

Question: Find the electric field a distance 'z' above the midpoint of a straight line segment of length 2L, which carries uniform charge λ Solution: Let me work out the steps and show you where my problem is(I have avoided showing some of the steps). The coordinate axis has been set up...

Hello everyone I have coiled an electromagnet over the weekend using iron and magnet wire, but when I connect it to my power source, the electromagnet becomes very hot. Is there some coating I can use to reduce the heat produced by the electromagnet when in use? Like epoxy or some sort of...

This is a concept question as I stated in my first post. For the equations there are the maxwells eqs: div E = rho/e0 div B= 0 curl E = -dB/dt curl B = u0*I + u0e0*dE/dt I created a simulation using Comsol and the flux lines, the vector potental, did rotate, but the vector potentials...

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Yes say the cylindrical magnet center is positioned at (1,1,1) then when the magnet rotates around its axis it rotates with the center never leaving (1,1,1) but when the magnet rotates in space it would rotate around (0,0,0), so it would go from (1,1,1) to (-1,1,1) to (-1,-1,-1) to (-1,-1,0) and...

Hello everyone, I have a quick concept question for electrodynamics course. If a cylindrical magnet, axially magnetized, is rotated round its own central axis, axis of symmetry, will this create a rotating magnetic field in the vicinity of the magnet? what if the magnet was rotated around in...