Why gravitational acceleration is zero at the centre of the Earth maximum at the poles and minimum at the equator?

1 Answer

The second and third facts depend on the distances of that points from centre of the Earth.

Explanation:

At the equator the distance of Earth surface is maximum because the geodethical shape of terrestrial globe and then the force minimum; at equator exists also a little addictional force that lightens gravitational force (because is opposite), the maximum centrifugal force for surface points of globe.
At poles the distance from centre of the Earth is minimum then gravitational force maximum.