Re: Apparent weight

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

My point of view is still that what we perceive as our weight (being heavy)
is NOT the downward pull of gravity but rather the upward push of the floor,
ground, chair.  We FEEL heavier if the push is greater than the _usual_
force due to gravity, and we feel lighter if that upward force is less.  We
FEEL as though we have normal weight when in a rotating space station if the
outside rim of that station is pushing us towards the center with an
acceleration of about 10 m/s^2.   We FEEL pushed back into our seats when
accelerated forwards and away from the center of a rotating frame if being
constrained to move in a curved path.  Dealing with these FEELINGS is (IMO)
important at any level in our physics instruction.  My approach is to
confront them directly.

I take consider the bathroom scale to be reading the Upward force needed to
maintain a zero acceleration (relative to the local frame)--others have
called this a Normal force.

This is an argument no one is going to win--again because we all have our
own comfort zones on this _and_ because we're not about to be conviced (or
haven't been through all the rhetoric) that one view is _correct_ and the
other _wrong_.

Rick



-----Original Message-----
From: Leigh Palmer <palmer@sfu.ca>

> Einstein freed us from the need to observe two kinds of
> forces which act on inertial masses. Why has it taken so long
> to convince physicists that he has done so? We don't live in
> an inertial frame of reference, and students instinctively
> know how to cope with that. Why do we insist on complicating
> their lives by telling them that some things they perceive
> with their senses are real, and some are fictitious, but only
> an ordained member of the faculty can tell them which is
> which?
>
> Leigh