Concept:The value of
g changes because the distance from Earth’s centre differs at different places on its surface.
Explanation:The Earth is not a perfect sphere.
It is flattened at the poles and bulges at the equator.
This means the Earth has an elliptical shape.
At the equator, the surface is farther from the centre of the Earth than at the poles.
Using the relation
g=r2GM, a larger radius
r gives a smaller value of
g.
Therefore, gravitational acceleration is less at the equator and greater at the poles.
This variation occurs because of the elliptical shape of the Earth.
Answer:B. elliptical shape of the earth