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Re: what to call little "g"



DSCHROEDER@cc.weber.edu wrote:

I like John's suggestions on what to call g. By the way, Serway's
fourth edition uses "freefall acceleration" instead of "acceleration
due to gravity", which is a big improvement as John notes. I'm quite
impressed that Serway has made an effort to improve his language,
here and elsewhere, even if some of the improvements are just patches.
As for what to call g in the second context, John's "local gravitational
constant" is the best I've heard. I've been saying "force per unit
mass due to gravity", which is a mouthful, even if it has the advantage
of reminding students that the units are N/kg. Of course, there are
a lot of simple dynamics problems where the answer ends up being something
dimensionless times g, and at that last stage, you want to again remember
that g has units of acceleration...

Dan Schroeder
dschroeder@cc.weber.edu

Why not simply call it the gravitational field? We have the electric field
and magnetic field which are ususally discussed in the second semester of the
beginning course. Why not introduce the field concept earlier as Serway does
in his *Principles of Physics*? My colleagues and I have used this idea for
years and it seems to keep a continuity in the concepts between mechanics and
E & M.

You have then
g=F/m gravitational field as the force per unit mass

and

E=F/q electric field as the force per unit charge.

The magnetic force, of course, is more complicated with the introduction of
the vector cross product, but introduced in the first semester the cross
product fits in nicely with the concepts of torque and angular momentum.

Roger