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Re: [Phys-l] NYT article: Centrifugal force

RE: and old thread:

By the way, there are indeed some real centrifugal forces. If you fling a
mass around in a circle on the end of a string, the force the mass exerts on
the string is centrifugal.

Steve Highland

Is it not a reaction to the centripetal force that causes the acceleration to the center? i.e. 3rd law.

One doesn't feel "it", unless there is some constraint. (which is what one feels) e.g. the centrifuge or at the end of the circling string.

bc can't, in his head, do the coordinate transformation even when not strapped in the centrifuge.

p.s. Am I overzealous?

On 2009, Jul 02, , at 12:46, Jack Uretsky wrote:

Seems basically fine to me, too. The earth is not an inertial frame; it
rotates. Centrifugal force is a tangible force that one feels, when one
sits in a rotating frame. There is nthing fictitious about it. It makes
the earth bulge.

On Thu, 2 Jul 2009, Peter Schoch wrote:

Well, I hate it. I work very hard to make sure my students know there
is no such thing as a centrifugal force, and that it is related to
Newton's Laws instead.

We want everyone to 'get it right' but don't impose criteria on
ourselves to make sure we don't perpetuate bad/sloppy thinking on such
matters as this. It wouldn't have taken him that much longer to
explain it more rigorously, and would've added tremendously to the
scientific worth and education of the public.

Peter Schoch

On Jul 2, 2009, at 2:53 PM, Rauber, Joel wrote:

Seems basically fine to me.


Joel Rauber, Ph.D
Professor and Head of Physics
Department of Physics
South Dakota State University
Brookings, SD 57007

-----Original Message-----
From: [mailto:phys-l-] On Behalf Of bettyjspace-
Sent: Thursday, July 02, 2009 1:29 PM
Subject: [Phys-l] NYT article: Centrifugal force

The following excerpt is taken from Tuesday's NYT, and the quote is
attributed to the associate director of the division of ocean and
climate physics at the Lamont-Doherty Earth Observatory of Columbia
University. Any thoughts with respect to the use here of the
centrifugal force?


The Earth?s Paunch
Q. I know the earth bulges at the equator. Does this include the

A. There is an oceanic bulge, said Arnold L. Gordon, associate
of the division of ocean and climate physics at the Lamont-Doherty
Earth Observatory of Columbia University.

?As the earth spins, a centrifugal force is directed outward, away
the axis of rotation,? Dr. Gordon said. ?This force is strongest
for a
particle at the equator that has a longer path to follow around the
earth?s axis each day, despite its greater distance from the earth?s
axis.? Meanwhile, he said, gravity, as induced by the earth?s mass,
also acting on each particle. The forces combine to produce what is
called the observed gravity, which does not point to the earth?s
center, but is off center.
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