Re: A weighty subject

[brian whatcott <inet@INTELLISYS.NET>]

At 20:40 10/16/99 -0400, Robert Carlson wrote:
...
> The definition that weight is the force of gravity does not rely on any
> manmade device such as a scale. //
> Weight has already been defined simply as the force of gravity.  Why
> introduce a manmade device into this definition?
> Nature does not give a damn
> about manmade devices, or whether we have figured out what she does.  She
> will do what she will do, regardless of what we think she will do based on
> our measuring devices.  Weight is the force of gravity is a beautiful
> definition and I do not want it bastardized.   //

Bob is sturdily defending a concept of weight.
 It would be fruitless to suggest this concept is itself,
a 'man made device' (though it undoubtedly is.)

In upholding W = mg    I expect Bob takes m as unchanging.
I believe he may well agree that a masses weight may vary
from place to place. Equator to pole, say.
 So he would easily agree that the g factor is what changes,
I expect.

 It is not clear to me which factors Bob takes
into account when considering the change of 'g'.

Does he like buoyancy?
Does he like effects due to Earth rotation?
Does he like effects due to varying r to Earth center?
Does he like effects due to gravitational anomalies?
(i.e varying sub-surface mass concentrations - 'masscons')

Some texts explicitly subsume items two and three under 'g',
others lead one to believe 'g' is a constant.

I would wish people to lead me to explicitly examine my
sense of how 'legitimate' is each of these unmentioned
components of 'g' in Bob's place.
Would he share with us?


Sincerely



brian whatcott <inet@intellisys.net>
Altus OK