Re: [Phys-l] Weightless

["Richard Tarara" <rbtarara@sprynet.com>]

I don't interpret what I feel in a jet aircraft accelerating forwards as
weight as John seems to imply below.  I feel pushed back into my chair. 
Same with the rotor-ride I feel pushed into the wall--not heavy.  However,
if I'm accelerated upwards I do feel heavier, and downwards lighter.  So,
maybe I'm misinterpreting what John wrote, but in my experience the
sensation of weight comes from vertical (or nearly so) forces with
different sensations from horizontal forces.  I think we might both agree
though that the sensation of weight in a rotating space station IS from the
surface we are standing on pushing us towards the center of rotation.

Rick


> [Original Message]
> From: John Mallinckrodt <ajm@csupomona.edu>
> Rick Tarara wrote:
>
> > For the 'apparent weighters' it is the apparent weight that is zero  
> > because
> > there is no force opposing the gravitational force and it is that  
> > opposing
> > force (usually the ground or chair) that provides us with the  
> > sensation of
> > weight.
>
> All we need in order to have "the sensation of weight" (I would  
> simply say in order to have weight) is the force from the chair, the  
> ground, the floor of a spaceship, or ANY other surface that is in  
> contact with us.  There is NO need for that force to oppose some  
> putative "gravitational force."  Moreover the sensation that one gets  
> in that situation is not merely "similar to" or "indistinguishable  
> from" the sensation that one gets when there "is" a gravitational  
> force to "oppose," it is IDENTICAL to that sensation because it is-- 
> in EVERY quantifiable aspect--the same situation.
>
> John Mallinckrodt
>
> Professor of Physics, Cal Poly Pomona