Recent content by lalligagger

Hi, I am a physics undergrad designing a solar spectrometer as part of a senior design type course. If we have light incident from the sun onto some sort of telescope objective (say a single lens for simplicity, focal length "f" and aperture radius "R") and then a pinhole at the focal point...

I am a physics undergrad (senior) with an interest in optics participating with three other undergrads (ME, EE, and CS) in a solar spectrograph build. It is a pilot program sponsored by NASA that will hopefully turn into a national competition. In addition to observing as many absorption lines...

Ok, A is the vector potential of B. Does A have any physical meaning or is it just an arbitrary vector that must exist because \nabla\bulletB=0?

Thanks Pion, but can you elaborate? What is μH and how does it relate to B? BTW, this is for a course that basically covers vector calculus that our math department doesn't in early calc classes. The question is really just about applying Stoke's theorem, which I understand pretty well...

Homework Statement Not going to write out the whole problem (yet). It's a "find the error in the incorrect proof" type of question in a section on curl and divergence. Homework Equations B = \nablax A is given as an equation of "electromagnetic theory" and used in the proof. It's...

Ok, so then is the cross section area in the equation of the fan or of the object?

Why is this? I also don't understand why the cross section area in your equation is for that of the fan and not the object. It seems to me that on a small object, a large fan would exert less force than a small fan displacing the same volume of air (at a faster velocity).

That doesn't sound like a direct conversion to me. The fan moves a given volume of air per time, but the force actually acting on the object would involve aerodynamics. How about some more details on the project?

That works, however the Biot-Savart law is easier to apply here and actually reduces to a formula identical to what you have written in the last line in the case of a long straight wire. B=µ0I/2(pi)r

You are trying to make the individual vector components match up, the sum of the components is fairly meaningless here.

Assuming my first assumption that energy = F x D Right, work is the energy added to or taken away from a system when it encounters a force over some distance. The definition of work is actually the integral, W=\intF\bulletdr Where dr is the change in position, the D in your equation. The...

CA is the column space of the matrix A and N(AT) is the null space of A transpose. Sorry, I thought that was standard notation. The argument says that given an arbitrary matrix A, the matrix ATA (the matrix you get when you multiply A by A transpose on the left) is invertible. The point of...

Sorry all my vectors look like superscripts, don't know what that's about. Homework Statement What is wrong with the following argument? Let A be an arbitrary m x n matrix. The vector A\vec{x} is obviously in CA so it can't be in N(AT) unless it's the zero vector, since CA is...

Homework Statement Determine the values of k, if any, that give the matrix (1,1,k),(1,k,1),(k,1,1) a rank of: zero, one, two, or three. Homework Equations The Attempt at a Solution I tried reducing to row echelon form but it's confusing dealing with all the k's. Is there a...