Re: A weighty subject

[Joel Rauber <Joel_Rauber@SDSTATE.EDU>]

Rick,
Nice summary of the W=mg camp. (definition (2) below.)
> To be sure, there are difficulties teaching any of the three primary
> definitions:
>
> 1)  W = mg (where g is dv/dt locally).
> 2)  W = mg (where g = GM/R^2)
> 3)  W = what the scale reads.

I've been changing my opinion and think that 3) as simply stated is not
tenable. Or else the weight of an oject changes when immersed in a fluid.
Leigh and John have convinced that we don't want that to happen in a
definition of weight.  I think 1) and 3) have to be amalgamated consistently
to include non-free fall frames, such as the elevator or the surface of a
spinning planet.

Joel