[Phys-l] Gravity?

["Espinosa, James" <JEspinosa@mail.twu.edu>]

Joel, I do mean by the "whole Earth" an integration over the whole Earth, assumed to be a sphere.  I believe, though am not sure, that Newton used or invented the integral calculus to do this calculation and found that the "distance" between the Earth and a particle on its surface would be the distance to the center of the sphere.
> From the start I stated that I would not confuse the students by taking into account the rotation of the Earth; I never have done that in my Freshman level physics class.  The rotation does require that "part" of the Earth's pull be "used" to produce the centripetal (not centrifugal) acceleration to produce circular motion.  This effect would slightly change the value of g versus a still Earth.  But, at the Equator, it would still not change the value of g when carried out  to 2 significant figures, which is all I do in class.

James Espinosa