The earth’s rotation doesn’t play a huge part in affecting the gravitational force we experience. Assuming the world was perfectly spherical, by my humble calculations, the difference between the acceleration due to gravity at the poles and the equator should only be around 0.03m/s^2.
I am lead to believe that the actual difference is also affected by the earth’s bulge at the equator. Apparently this increases the distance between the centre of mass of the two bodies (i.e., you and the earth) which results in a lower acceleration due to gravity value at the equator.
Like compressor stall and gaunty said, gravity is an attracting force between two bodies with the magnitude of the force depending upon the mass and distance between the bodies. The force decreases/increase in proportion to the square of the distance, i.e. 1/(distance)^2.
Have a good one, Dave.
[ 16 August 2001: Message edited by: Dave Incognito ]