Explain the factors affecting the value of g .

Explanation

The following factors affect the value of gravitational acceleration of the earth (g)
(i) shape of the earth :
(a) The shape of the earth is not perfectly sheprical. It is slightly flattened at the poles and bulged at the equator
(b) As a result, the radius of the earth at the poles is less than that at the equator.
(c) Hence, the value of g is highest at the poles `(9.832 m//s^2)` and decreases slowly with decreasing latitude. it is the lowest at the equator `(9.78m//s^2)`
(ii) Height :
(a) As the height of an object from the surface of the earth increases , the distance between the object and the centre of the earth (r) increases.
(b) As a result, the value of g decreases with increase in height .
Depth :
(a) The value of g is maximum on the surface of the earth
(b) As depth of an object increases , the distance between the object and the centre of the earth (r) decreases.
(c ) Along with the distance, the part of the earth which contributes towards the gravitational force felt by the object (M) also decreases.
(d) Thus, due to hte combined effect of changing vlaue of r and M, the value of g decreases.
(e ) At the centre of the earth , the value of g becomes zero