Re: [Phys-l] Weightless

[John Mallinckrodt <ajm@csupomona.edu>]

But if an astronaut isn't "weightless," then what is?  Isn't the word  
of absolutely no use if we can't apply it to astronauts?  Weight  
implies "heaviness" and heaviness implies (to me) a tendency to stay  
"pinned by gravity" to some surface.  If a person (or thing?) finds  
that she (or it?) has absolutely no such tendency, then it seems to  
me that she has every right to say that she is "weightless" and that  
we ought to agree with and abide by her assessment.

There's certainly no problem justifying any of this from a Newtonian  
viewpoint.  It's simply a matter of deciding what you want to mean by  
"weight."  I don't see any good reason to require that it mean the  
same thing as "gravitational force."  Indeed, it seems to me a  
genuine disadvantage.

Anthony Lapinski wrote:

> I agree. This is why I discuss bathroom scales and apparent weight. If
> someone says there is gravity acting on the astronauts AND they are  
> also
> weightless, it ads to more confusion...
>
> [Rick Tarara wrote:]
> > In the 'g' thread, we've (yet again) opened up the definition of  
> > weight
> > debate.  While I see certain pedagogical advantages to either of  
> > the two
> > main approaches, I would ask if the proponents of saying that one IS
> > weightless while in the space station can explain that from a  
> > Newtonian
> > viewpoint?  Seems to me that there is only one force acting on the
> > person.
> > If we call that the gravitational force due to the earth, then what
> > (again
> > in the Newtonian viewpoint) is weight?  Isn't this gravitational  
> > force a
> > component of your weight?  But it is the only component here in the
> > Newtonian view and is not zero!

John Mallinckrodt

Professor of Physics, Cal Poly Pomona
<http://www.csupomona.edu/~ajm>

and

Lead Guitarist, Out-Laws of Physics
<http://outlawsofphysics.com>