Re: gravitational sensations--was Work/Energy theorem ?

[sample@lyon.edu (John D. Sample)]

At 3:19 PM on 4/7/97, <phys-l@mailer.uwf.edu> wrote:

> At 11:15 AM 4/7/97 -0700, you wrote:
> > I never interpret or teach the upward force of the ground as my weight!
> > I can't think of a more confusing interpretation. I teach my students
> > that weight is the force of gravity which acts downward on everyone.
>
> I always had trouble explaining the Ferris Wheel problems until I started
> suggesting that our sensation of weight is due to the upward force that
> opposes gravity and keeps us from falling.  This, IMHO, gives a much more
> cogent explaination of why the rider feels near weightless at the top and
> feels twice as heavy as normal at the bottom of a Ferris Wheel moving at the
> appropriate speed.
>
> Stanley J. McCaslin                     Inet: mccaslin@bobcat.peru.edu
> Assistant Professor, Computer Science   Phone:402/872-2208
> Peru State College, Peru, NE  68421     Home: 402/872-7595

I think it's common to distinguish between the weight, ie the force of
gravity, and the variable normal force on your seat by refering to the
latter as the *apparent weight*.  So the apparent weight is what is
measured by your bathroom scale and, unless you put it in an elevator
(which apparently many people do since there are so many problems
concerning this situation in texts), your apparent weight equals the pull
of gravity.

Then the astronauts are still influenced by the gravity force (they have
weight), but their apparent weight is zero.

I'm not sure this helps much.

J. D. Sample                          (501) 698-4625
Math-Physics Dept                     sample@lyon.edu
Lyon College
2300 Highland Road
Batesville, Arkansas 72501