Re: Apparent weight

[phrp@bigcat.fhsu.edu (Roger Pruitt)]

Richard W. Tarara wrote:
> -----Original Message-----
> From: Leigh Palmer <palmer@sfu.ca>
> To: phys-l@atlantis.uwf.edu <phys-l@atlantis.uwf.edu>
>
> > > What Roger says below is how I try to resolve the problem in my classes; I
> > > don't define weight as the force of gravity on an object, but rather as
> what
> > > the "bathroom" scale reads.
> >
> > Since this definition of weight is so much simpler than the "force
> > of gravity" definition, why does anyone think it is conceptually
> > more difficult?
>
> Because it requires that one understand _how_ a bathroom scale works versus
> how a triple-beam balance (or similar device) works.  This definition is
> DEVICE dependent and therefore unsatisfactory--to me.
>
> Rick

I think you are making it too hard, Rick. Leigh asked for an operational
definition. What I offered was such a way of defining weight. I don't
care to know how the bathroom scale works, nor do I think that is
important. The number I get when I stand on it is my weight. 

I take the scale with me in the shuttle and "stand" on it and get zero.
Therefore, I'm weightless.

The force of gravity is acting on me in both situations, but I choose to
not talk about the force of gravity on me as my weight in my beginning
classes. Thus I avoid many problems. I have written before that in the
equation F=mg that I refer to the g as being the gravitational field and
introduce this concept early. F=qE then follows naturatlly.

Roger


-- 

================================
|  Roger A. Pruitt, PhD        |
|  Department of Physics       |
|  Fort Hays State University  |
|  Hays, KS  67601             |
|  Ph. (785) 628-5357          |
================================