Recent content by cephas

How do I determine how much current a wire can safely handle? I made some electromagnets with some coil and 9 volt batteries, but the wire and the batteries get real hot after a minute, which I assume is not good so i don't keep it connected for long. I want to know how much the wire I am using...

Ok, now I got it so it contracts like it is supposed to. I don't understand why i have to take the reciprocal of gamma though. I will try studying my books some more.

Why would I need to relate u and t? x=Cos(u) just means I am transforming all x coordinates from 0<=u<=2Pi to x' I don't see why they need to be related. Also, when I tried doing this, the circle stretched. I thought is was supposed to shrink. I have to be doing something wrong.

I also have a question on black holes. It kind of crosses over to quantum mechanics though. I hope that is ok. Since a black hole is considered to be a singularity wouldn't that violate the uncertainty principle?

I am trying to understand how to use the lorentz transformation to calculate things and I have a few questions about it. Suppose I have a circle of radius 1 in frame K which is at rest. Frame k' is moving at velocity v relative to frame k. What would the circle look like to someone in frame...

I have also been looking for some good introductory books to quantum mechanics. After some searching online I found a book that looks promising. It is one by A. C. Phillips. It is a paperback edition that only costs about$43. It says it has answers to the problems in the review of it, but...

let me just check my understanding real quick on the tensor product. So dx and dy are 1-forms. They are also linear functionals. So how does dx and dy operate on a vector? Is it the same as the derivative? dx(x)=1 or dx(x^2)=2x? I am not quite sure I get that... And then with the...

more on 1-forms okay, thanks so much, that clears up a lot of stuff. Now a few more questions. First off, I was wondering if the 1-form or any differntial form for that matter is independent of the function on the manifold. What I mean is do you get the same 1-form for all functions on...

a few questions on 1-forms I reread all the main stuff you posted lethe, and I think I am understanding it a little better. I just need to ask some questions to make sure I am on track. In equation 4. dƒ(v) = v(ƒ) is the d, which is the linear functional, actaully the diffenrial form for...

lethe, I discovered this thread on that other site a while ago, then more recently discovered it on this one. I was very excited to find it, as it contains math I don't yet know and is actaully being aimed at someone with my level of math (completed multivariable calc). However, I have been...