22 December 2007

What is power?

From Walter Lewin's 8.01 Lecture 14, about 14 minutes in:

"What is power? Power is work that is done in a certain amount of time. dw/dt, if w is the work, is the instantaneous power at time t. We also know power in terms of political power. That's very different. Political power, you can do no work at all in a lot of time and you have a lot of power. Here in physics, life is not that easy."

This reminds me of the classic claim that, say, bricklayers do more work than lawyers, because work is force times distance, and bricklayers are exerting much larger forces when they lift things, since bricks are heavier than pieces of paper. This is a sort of translingual pun, the two languages being English and scientific jargon.

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