Re: [Phys-l] Weightless (running around in circles)

[Stefan Jeglinski <jeglin@4pi.com>]

> On 11/22/2006 05:19 PM, Richard Tarara wrote:
>
>  > If I strap the accelerometer to me, as I sit here, I would think it would
> >  read zero. 
>
> No.  Not for real-world accelerometers ... as you can see here:
>   http://www.airworlduk.com/2004pix/accel.jpg

Even trying to correct for parallax looking at the picture, it seems 
that it is reading more than 1g. But aside from this trivial and 
unimportant observation...

If I hold such an accelerometer in my hand (so that it is attached to 
my local reference frame), and suddenly an "ideal" trap-door in the 
floor opens (t=0) and me and my accelerometer fall through "in ideal 
fashion" (IOW pretend there is no drag, no rotation due to my spastic 
twisting when I realize I'm falling, etc), I submit that the 
accelerometer will not change its reading, even momentarily. From 
t=0, every particle in the accelerometer and me are falling together, 
and by looking at the accelerometer alone, it's as if we were still 
standing on the floor.

Am I wrong about this?


Stefan Jeglinski