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



I'm fine with that definition. Now can we get the astronauts to stop telling everybody that they are weightless, and in Zero G? And what about those Weightless Flights of Discovery in the vomit comet?

As much as we'd like to redefine it, we've lost control of the word. Astronauts floating in free-fall are always going to be called weightless, and the general public is going to continue to believe that there is no gravity in space (or even on the moon!).

Scott


* /From/: "Rauber, Joel" <Joel.Rauber@SDSTATE.EDU
<mailto:Joel.Rauber%40SDSTATE.EDU>>
* /Date/: Mon, 8 Nov 2010 08:34:44 -0600

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Interestingly, the current issue of TPT (The Physics Teacher) has a short
article by Al Bartlett who weighs in on this after a long distinguished career
in physics. The simple one sentence definition of weight that he proposes is:

"Then the weight of a mass M in a specified frame of
reference is M times the free-fall acceleration in that specified
frame of reference."

This is not contrary to several versions proposed on this list and their
authors websites. Bartlett precedes the above definition with the following
admonition: "All of this awkwardness can be avoided if we always
replace the terms 'acceleration of gravity' and 'acceleration
due to gravity' with the more accurate term "free-fall acceleration." Read the
article for details.