Re: OT: Speed of light [was Re: Why not a Python compiler?]

Dennis Lee Bieber wrote:

On Tue, 12 Feb 2008 00:18:38 -0800, Erik Max Francis <max@xxxxxxxxxxx>
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 && max@xxxxxxxxxxx && 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
.

Relevant Pages

  • How forces work
    ... Is that the one where "m" is mass in grams? ... It is pushing up with the same force as my weight. ... >> The chair is only pushing down with 980 newtons if it is massless. ... Or you skimmed through A Brief History of Time, or perhaps The Physics ...
    (sci.physics)
  • Re: My new spreader beam plan (visited steel yard)
    ... And how does your grocer measure the "mass" of a pound? ... Until fairly recent times there was no practical way to measure mass. ... You know that GRAVITY IS APPLYING THE SAME FORCE TO BOTH ... Weight, measure of the gravitational force exerted on an object (see ...
    (rec.crafts.metalworking)
  • Re: So, I got my OW Cert
    ... chemistry or physics... ... of sugar with a "net weight" of 2 kg or of 4 lb or whatever, ... quantity physicists like to refer to as "mass". ... one with several different meanings. ...
    (rec.scuba)
  • Re: My new spreader beam plan (visited steel yard)
    ... like 1/30th or so of a pound. ... Gyngaard sez: ... Weight is not, and never has been, a force, when we talk about the "net ... And how does your grocer measure the "mass" of a pound? ...
    (rec.crafts.metalworking)
  • Re: Log Peridic 50m - 1300m
    ... If you use pounds in a formula that wants mass ... you will note that pound(mass)* feet/s^2 is NOT the pound force unit. ... weight on the moon. ... Gift Giving Made Easy ...
    (rec.radio.amateur.antenna)