Re: centrifugal force

["Bob Sciamanda" <trebor@velocity.net>]

When NASA accelerates a man strapped into a sled  along a LINEAR track,
the man's face is squished inward (toward the rear).  But in this linear
case we don't seem to be tempted to ascribe these effects to a newly
named force.  These strains are the effect of stresses arising from the
transmission of forces among the parts of an accelerating body - the
centrifugal effect is no different and should not be treated differently.
I would speak of a centrifugal effect, not of a centrifugal force
(within the context of Newtonian mechanics).  Both the linear and the
rotational effects are "inertial" effects arising whenever external
forces attempt to distort a composite system by DIRECTLY accelerating
only some component parts (you might call it a "tidal" effect).  Internal
"connections" are then stressed as the directly accelerated components
accelerate, distorting the system configuration.

(Sorry, but I was quiet the last time this can of worms was opened!)

-Bob

Bob Sciamanda   trebor@velocity.net
Dept of Physics
Edinboro Univ of PA  http://www.velocity.net/~trebor
Edinboro, PA   (814)838-7185
-----Original Message-----
From: DEVARAKONDA VENKATA NARAYANA SARMA <narayana@hd1.vsnl.net.in>
To: phys-l@atlantis.uwf.edu <phys-l@atlantis.uwf.edu>
Date: Wednesday, April 29, 1998 11:03 PM
Subject: Re: centrifugal force


> At 07:05 AM 4/29/98 -0400, you wrote:
> > http://www.observe.ivv.nasa.gov/nasa/space/centrifugal/centrifugal_entr
y.html
> > The above reference (NASA educational item) is devoted to CENTRIFUGAL
force.
> > From the NASA site
> ------------------------------------------------------------------------
--------
> Because the centrifugal force exists only in rotating reference frames,
but
> not in inertial reference frames, it's sometimes called a "fictitious"
or
> "pseudo" force.
>
> We don't like this characterization because there is nothing fictitious
or
> pseudo about it when your car goes off the road and crashes, or when
your
> bicycle skids out from under you when cornering a slippery curve. The
> Earth's equatorial bulge is not a fiction, nor is the problem an
engineer
> confronts when designing turbine blades of jet engines that have to stay
> together at rotation rates of up to 100,000 revolutions per minute.
> ------------------------------------------------------------------------
--------
> It is not the centrifugal force that causes the damage to vehicles and
> occupants but the work done by the obstacles in the path of the car in
> stopping the car . Once the car has gone off the track there can be no
> centrifugal force, Is it not? The kinetic energy of the car is used up
> in doing the damage.
>
> But then there is no use. If NASA itself joins the "centrifugal
> band-wagon"...
>
> regards,
>
> sarma.