Dennis Lee Bieber wrote: > On Tue, 12 Feb 2008 00:18:38 -0800, Erik Max Francis <[EMAIL PROTECTED]> > declaimed the following in comp.lang.python: > >> equivalence for everyday usage and make no requirement of using the >> "proper" units for mass (kg) vs. weight (N) for, say, buying things at > > Ah, but in the US, the unwashed masses (as in "lots of people") > don't even know that there is a difference between lb-force and lb-mass > (okay, all they know of is a simple "lb" which is based upon force of > gravity at point of measurement, while lb-mass is a sort of artificial > unit... don't mention slugs <G>)
Yes, exactly; you started with another word game and then in the process dismissed it with a half-joke at the end. Pounds came first, and rationalized systems (lbm/lbf, slug/lb, and even ridiculous retrofits like kg/kgf, completely turning the apple cart upside down) came afterwards. The point is, the difference between the two is _totally irrelevant_ to those "unwashed masses" (and in the contexts we've been talking about). Even NIST (among other) SI guidelines acknowledge that because, well, it's blatantly obvious. That actually feeds right back into my earlier port about physics subsuming terminology to its own ends. Making the distinction between mass and weight is critical for understanding physics, but not for everyday behavior involving measuring things in pounds; after all, in extending the popular concept of a "pound," different physicists made a distinction between mass and weight differently (i.e., the rationalized systems above) such that there is no accepted standard. Of _course_ physicists have to make a distinction between mass and weight, and to do so with Imperial or American systems of units requires deciding which one a "pound" is, and what to do with the other unit. But that's a physicist making distinctions that do not exist in the more general language, just the same as a physicist meaning something different by "free fall" than a layman. But (say) dinging some Joe Schmo because he doesn't know that a pound is really a unit of force (or mass) is really just playing pointless word games. As I said earlier, there are better ways to teach physics. -- Erik Max Francis && [EMAIL PROTECTED] && http://www.alcyone.com/max/ San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis Don't ever get discouraged / There's always / A better day -- TLC -- http://mail.python.org/mailman/listinfo/python-list
