Re: Misconceptions--a comment

[Leigh Palmer <palmer@sfu.ca>]

> In a message dated 98-02-14 21:03:11 EST, Rick Tarara writes:
>
> << The point is, that whether you operationally define weight as what a
> bathroom scale measures or as the net force towards the center of a nearby
> large gravitational body, or just as THE force of that large gravitational
> body, there are subtleties that you will have to deal with.  The choice
> seems to be much more a question of personal taste and the degree to which
> one has developed a consistent set of instructional tools that address the
> choice.  To this end, it is very hard to say that any of the popular text
> books are _wrong_, only that they might not conform to one's personal
> choice. >>
>
> Rick,
>
> I agree with most of your post, but have never seen weight defined in any
> physics text book as what a bathroom scale reads.  I believe that words have
> meanings, especially in the sciences, and when we stray from the definitions,
> then we are opening the door to confusion.  All of the respectable sources I
> have examined give the same definition for weight.  I realize that various
> situations can be used to examine the meaning of weight, but when all is said,
> the definition still is the central focus, regardless of personal taste.
> Else, how are we to communicate?
>
> Bob Carlson
                                                  _    _        _
Come on, Bob! Will you buy a definition of weight W = mg, where g is the
acceleration with respect to the Earth's surface of a freely falling body
at rest at the position in question? If so, you will perhaps be surprised
to learn that this is *exactly* the same as my definition applied to the
same frame of reference. What is your definition of weight on the Moon?
If you have an equivalent definition for weight on the Moon, what, then,
is your definition of weight in an elevator? If it differs in form from
your definitions of weight on the Moon and on Earth's surface, how do you
justify the difference?

Leigh