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# Re: Kinematic equations

And once again I have to ask: Where is the problem? Maybe I'm
used to my terminology too much, but to me 'g' is an
acceleration: When I let a body fall (air removed) it IS
accelerated with a~9.8 m/s^2. This value *describes* what happens
(and in what way), it doesn't give a reason why.

g is the gravitational field constant. It is a unit force, the force
on 1 kg of mass near the surface of the earth. It is analogous to
the electric field constant (E = F/q) and we can describe the
magnetic field in a similar manner (B = F/Il). The common
description of g as the acceleration due to gravity comes out of an
analysis of free fall where for an object falling freely

Fnet = ma and Fnet = Fapplied + Ffriction

For a sufficiently dense object falling a short distance near the
surface of the earth Fapplied = mg and Ffriction = 0.

then Fnet = ma and Fnet = Fg + 0
i.e. Fnet = mg

So ma = mg and a = g.

That is, the acceleration of a freely falling body equals the
gravitational field constant. This treatment I believe is important,
g is the gravitational field constant, the accleration of a freely
falling body equals g, g is NOT defined as acceleration. Defining
g, E, and B as field constants enables us to make important
connections between gravitational, electric, and magnetic phenomena
and permits to begin to examine elementary field theory.

my \$0.02 :)

Don Metz Phone: 204-786-9241
Collegiate Division Fax: 204-775-1942
University of Winnipeg email: dmetz@collegiate.uwinnipeg.ca
515 Portage Ave.
Winnipeg, MB