Re: Apparent weight

[Leigh Palmer <palmer@sfu.ca>]

> Most elementary physics texts (and students) use the term gravity in two
> ways: (A) as a phenomenon which manifests itself (or is responsible for)
> weigth or free fall and (B) as a synonyme, sometimes for gravitational
> acceleration and sometimes for m*g. I try to emphasize precision but I
> am not very pedantic about it.
>
> The principal of equivalence is often stated in textbooks but it is not
> emphasized in the first semester. (Many of my students have hard time to
> learn the difference between v and a). Same is true or the relative nature
> of velocity; we do not always say "with respect to the road". Adding another
> ambiguity to the term gravity is not desirable, in my opinion. The
> gravitational pull (toward the center of Earth) in the orbiting shuttle, I
> say, is about the same as at the sea level but the "apparent weight' is
> nearly zero, as in a free-falling elevator.

I see. Gravity is responsible for weight, and in the case of the shuttle,
it is responsible for weightlessness. I'm sorry, Ludwik; that would utterly
confuse me if I didn't understand the topic thoroughly. Understanding it, I
reject it. Please give me an operational definition of either "gravity" or
"gravitational field". Otherwise the question of "What is the gravity in
the space shuttle?" cannot be resolved except by your adjudicating it.

Leigh