Built on Facts

I love teaching, but I have to say I am not a fan of teaching the summer session. Everything is way too disorganized. Oh well, at least it’s only for another three weeks or so.
The way undergraduate intro physics is taught is usually in two halves, and right now I’m teaching the second. [...]

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Yesterday in my recitation section I went through the chapter on electromagnetic induction, covering Faraday’s law and the displacement current term in Ampere’s law before assigning a quiz. Though this quiz really doesn’t need those concepts, it was a good opportunity to break out my all-time favorite Intro E&M quiz question.
Consider two parallel wires [...]

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I gave this quiz to my Physics 208 class this Monday, modified slightly from one of the textbook homework problems. I was going to work it out here, but I think I’ll leave the solution as a challenge for you.
A straight conducting wire of mass M and length L is placed on a frictionless [...]

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A couple days before I started teaching recitation sessions for Physics 208 (the E&M half of calc-based intro physics) this summer, I found out that in fact I was not teaching the second summer session, I’m teaching for the second half of the full summer session. Turns out there is a difference! For [...]

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When I was a young child, my uncle Fred used to try to convince me of some pretty outlandish things. His favorites were to say that the earth was flat and that England was a hoax. I was old enough to know better and I tried to argue as best I could, though [...]

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A while back the county government in my home town was considering a request from a phone company to construct a new cell tower to bring cellular service to a rural area. The government balked, largely for aesthetic reasons, though they couched their opinion in safety terms. They said they were concerned about [...]

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Like the Batman problem a few posts down, there’s another classic failure which has reached internet fame and glory by virtue of its spectacular flameout.

Wonderfully eccentric, but the sad part is that the problem is literally one line away from a correct solution. The block starts off with a gravitational potential energy mgh. [...]

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There’s a test problem famous by virtue of the fact that one student failed to answer it, but did so in a hilarious way. You’ve probably seen it, and here it is:

Let me quote the problem in case it’s hard to read.
A proton approaches a long line of positive charge so that with its [...]

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My intro physics text in my undergraduate education was by Halliday, Resnick, and Walker. I personally thought it was a quite good text, but what particularly stood out was its obsession with penguins. Probably a dozen or more problems involved penguins in very improbable situations. It was pretty funny. But there’s [...]

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The divergence theorem? Gauss’ law? If you’ve had college physics, at least the second is familiar to you. Now those two things are really fascinating, and I’m going to put a math-lite layman’s explanation in a future post. But hey, it’s spring semester finals time and that means all you people [...]

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