Re: [Phys-l] A question about the Earth's gravity

["M. Horton" <scitch@verizon.net>]

Not somewhat.  A small fraction of 1 percent closer.  The equatorial 
diameter is 12,760 km and the polar diameter is 12,740.  That's a difference 
of 0.16%.  I wouldn't consider that to be "somewhat" closer.  It is a 
well-established misconception that the earth is a highly oblate sphere.  It 
is a very nearly perfect sphere.  The eye could certainly not distinguish it 
from a perfect sphere.

As a demonstration, have Microsoft Word draw an 8-inch circle on a sheet of 
paper.  Then have it draw another that is 8 inches horizontally and 7.987 
vertically.  That is a scale model of the earth and your eye will not be 
able to distinguish the two.

Don't even get me started on the elliptical orbit of the Earth.  ;-)

M. Horton

----- Original Message ----- 
From: "chuck britton" <cvbritton@embarqmail.com>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Thursday, May 07, 2009 6:29 AM
Subject: Re: [Phys-l] A question about the Earth's gravity


Also the poles are somewhat closer to the center of the earth.

On May 7, 2009, at May 7(Thu) 9:06 , Rauber, Joel wrote:

> Its only somewhat above the level of AP-C if centrifugal effects
> are deemed somewhat above the level AP-C
>
> _________________________
>
> Joel Rauber, Ph.D
> Professor and Acting Head of Physics
> Department of Physics
> South Dakota State University
> Brookings, SD 57007
> Joel.Rauber@sdstate.edu
> 605.688.5428
>
> > -----Original Message-----
> > From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
> > bounces@carnot.physics.buffalo.edu] On Behalf Of Fakhruddin, Hasan
> > Sent: Thursday, May 07, 2009 7:46 AM
> > To: Forum for Physics Educators
> > Subject: [Phys-l] A question about the Earth's gravity
> >
> > We claim that the earth's gravity at its poles is slightly greater
> > than
> > that at its equator.  However, I feel justification for it is not
> > trivial but somewhat above the level of even AP Physics C; it will
> > require quite a bit of calculus!  Would you agree?
> >
> > ~ Hasan Fakhruddin
> > Instructor of Physics
> > The Idiana Academy for Science, Mathematics, and Humanities
> > BallState University
> > Muncie, IN 47306
> > _______________________________________________
> > Forum for Physics Educators
> > Phys-l@carnot.physics.buffalo.edu
> > https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
> _______________________________________________
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