Re: little gee and its sign

["John S. Denker" <jsd@MONMOUTH.COM>]

At 02:39 PM 9/14/01 -0400, Hugh Haskell wrote:
> I have been campaigning for
> years to eliminate the phrase "acceleration due to gravity" from use
> in connection with "g."

I am totally mystified by this campaign.

> It is too easy for students taught with this
> concept to come to the conclusion that *all* accelerations are 9.8
> m/s^2!

Does mentioning "the density of gasoline" cause them to conclude that all
densities are equal to 6 pounds per gallon?

Does mentioning "the price of beans" cause them to conclude that all prices
are equal to 57 cents per pound?

Any student who cannot distinguish statements about one member of a class
(one particular acceleration) from generalizations about all members of a
class (all accelerations) has a linguistic and/or conceptual deficit of the
most profound sort.  This deficit must be dealt with.  It must be dealt
with directly.

Until this deficit has been overcome, talking about physics concepts (such
mass, force, acceleration) is hopelessly remote from the real problem.

> It is clearly *not* an acceleration,

Little g(x) most certainly is an acceleration, at each and every point (x).
 Loudly asserting that it is not won't change anything.

Anybody who disagrees is requested to provide some theoretical and/or
experimental methods for disproving the assertion that g(x) is an
acceleration.

> and the fact that some
> objects fall with accelerations near that value is not relevant.

It's relevant to me.  It was relevant to my friend Albert.

> I think the most accurate description of g is that it is the
> proportionality constant between mass and the force of gravity on
> that mass.

-- I don't think so.  Albert didn't think so.
-- Describing it as an acceleration is equally accurate whenever both
descriptions apply, and more accurate in the cases where the F/m
description does not apply (e.g. massless objects).

> The question is, what do we call "g" (not that it needs a partiuclar
> name, but the students want one).

Indeed they do.

> I have opted for "gravitational field strength,"

That's fine.

> it is nice to point out to the
> students that physics isn't always so cut and dried as they like to
> think.

I agree with the sentiment, but fussing with g doesn't seem to be a good
way to illustrate the point.