Monday, March 19, 2007

the past week

It was a hectic week with its ups and downs. It's invigorating to be busy, outside the office, for once. I've escaped some shite from work as a result, and that's always a good thing.

I could kill myself for not having more initiative, for retreating into the comfort of familiar companies, for that almost pathological flaw... It had happened more than once. I do fine when dealt mediocre cards, but falter when I get the best hand. What's wrong with me?

I'll be on the roads again! That's more $$ down the drain. Now, I'm not even sure if I have enough to spend on my holiday.

Intentionally or otherwise, she declared herself out-of-bounds when she mentioned her bf at lunch today. Gah.

Maybe I'm numb to all the blood and gore they show in the theaters these days, but the chopped heads and blood in 300 looks curious and surreal. The scenes where the severed heads spent some theatrical seconds in midair gyration just looked like animated Surrealist artworks. There wasn't even disgust to speak of. Weird huh. My friend thought better of the animation shown with the ending credits. Xerxes' creatures look so fantasical, like some rip off from LOTR. Oh, and the word "freedom", when used in movie dialogues these days, inevitably reminds me of Dubya.

It feels great to be playing in an orchestra again. My intonation got better, but I'll still need to work on the semi-quaver passages. I wouldn't mind helping out in group again, but just not every week. It keeps the fingers nimble and the mind alert (I sound old).

Tutoring throws out rather interesting questions at times. My E&M has always been shaky, so I'd appreciate any ideas on this. From Maxwell's 4 equations and the Force Law (\vec{F} = q(\vec{E} + \vec{v}\times \vec{B})), and induced emf can arise in two ways --- moving a conductor through a magnetic field (the Force Law's at work here), or varying the magnetic field in a loop (Faraday's Law \vec{\nabla} \times \vec{E} = -\frac{\partial \vec{B}}{\partial t}). So the question is, what's the electrical potential in a wire loop in which emf is induced by one of these mechanisms? The suggested solution set claims the absence of any potential difference in the loop when the emf is induced by the Force Law, since only magnetic forces are at work here. The solution stops short of explaining what happens when induction arises through Faraday's Law. An electric field will be induced in this case, but since \vec{\nabla} \times \vec{E} \neq \vec{0}, unique values for the electric potential cannot be defined at each point in the loop. What then is the resolution to this? The problem is described in the final paragraph on this page.

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