Re: Kinematic equations

[Don Metz <DMETZ@collegiate.uwinnipeg.ca>]

> 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
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