Question

variation of g due to rotation of earth​

Answer 1

Rotation of Earth creates a Centrifugal force

Mv^2/r

As the r changes so does the Centrifugal force. So zero Centrifugal force will be at poles as r is zero and maximum Centrifugal force will be at equator as r is equal to R.

Centrifugal and gravitational force are opposite in direction. So gravitational will be relatively less on equator and more on poles because of the rotation of Earth.