Re: [Phys-l] definitions ... purely operational, or not

["Dr. Richard Tarara" <rtarara@saintmarys.edu>]

----- Original Message ----- 
From: "Rauber, Joel" <Joel.Rauber@SDSTATE.EDU>
> I think you've correctly analyzed what drives the discussion.  Is it fair 
> to say that you are using the "Bartlett" definition of weight, but with 
> the proviso that one always choose the earth surface frame of reference? 
> (I don't think you are equating weight with GMm/r^2, i.e. Newtonian 
> gravitational force, or are you?)
Correct--Weight = mg with g as measured by someone standing on 'earth'. 
However, if one goes to the moon, weight would involve the local free-fall 
acceleration as viewed from the moon's surface.  I do have a project (for my 
gen-ed students) determining the performance in several Olympic events if 
the games were conducted in an air filled dome, on the moon.

With all the problems we do in intro courses that include the 'mg' force (or 
components of such in the case of inclines), it is natural to name that 
force.  Weight seems to be the concensus choice--at least by text-book 
authors--and I have no problem with that.

Rick