Re: [Phys-l] Weightless

[John Denker <jsd@av8n.com>]

On 11/21/2006 02:00 PM, Anthony Lapinski wrote:
> In my view the free body diagram on the astronaut shows one arrow pointing
> toward the Earth. It is the weight of the astronaut, or mg (g = 8.7 up
> there). The astronaut is in free fall, and they have plenty of weight. It
> is this force which makes them accelerate in orbit. But the scale reads
> zero, so they have no apparent weight.
>
> This is more clear to me, but we each have our own way of explaining
> things.
>
> Anybody out there with a different way of explaining "weightless"
> astronauts?

Does anybody out there /not/ have a different way of explaining
weightlessness???

What was called "apparent weight" in the passage quoted above is
properly called "weight" in nearly all practical situations.  The
astronauts have zero weight in the spacecraft frame.

What was called simply "weight" (as in "plenty of weight") I'm
not quite sure about, but probably it is something like the
force of N-gravity ... which in turn is approximately but not
exactly the weight in the lab frame.

Question:  At temperate latitudes, in the usual lab frame, how much
does N-gravity differ in magnitude from E-gravity?

If you are going to use E-gravity to define weight in the lab frame
when weighing things in the ordinary way -- as you must if you want
to get decent accuracy -- why not be consistent and use E-gravity to
define "the" weight in the spacecraft frame?

  http://www.av8n.com/physics/weight.htm#main-total-acceleration