question_answer

Acceleration due to gravity:

A)  decreases from equator to poles

B)  decreases from poles to equator

C)  is maximum at the centre of the earth

D)  is maximum at the equator

Correct Answer: B

Solution :

 Key Idea: Equatorial radius is nearly 21 km larger than polar radius. The value of acceleration due to gravity varies from place to place at the surface of the earth and also as we go above or below the surface of the earth. At the surface of the earth the value of g is minimum at the equator and maximum at poles. It has two reasons; the shape of the earth and the axial rotation of the earth. Earth is not a perfect sphere but somewhat flat at poles and slightly bulge at equator. \[g=\frac{G{{M}_{e}}}{R_{e}^{2}}\] where Mg is mass of earth. As we go from the poles towards the equator the radius \[{{R}_{e}}\] goes on increasing and hence the value of g goes on decreasing.