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Re: displacement and graphs



I wrote:
> As mentioned previously, displacement generally means
> position relative to some arbitrary reference.

Then at 07:45 AM 10/10/01 -0500, RAUBER, JOEL wrote:

A quick cursory glance at the four introductory texts in arms reach define
displacement not as above, but rather as r_2 - r_1, i.e. as change in
position.

Tipler page 19
Halliday and Resnick "Physics" page 37
Crummett & Western page 41
Lea & Burke page 32

Those represent a less-general usage, a special case. There's nothing
wrong with special cases, so long as they are recognized as such.

I stand by what I wrote. The first two books within the reach of *my* arms
agree with my more-general usage:
*) _The Feynman Lectures on Physics_ volume I page 47-4 et seq.
*) Sears, _Principles of Physics_ page 481 et seq.

This is general case. Citing examples of less-general usages is not going
to prove anything.