Question

Why is the value of '$g$' minimum at the equator?

Answer 1

Step 1: Acceleration due to gravity

1. Gravitational acceleration is greatest at the poles and least near the equator. An object's gravitational acceleration is a measurable quantity. According to Newton's universal law of Gravitation, the value of gravity depends on the mass of the Earth and the distance of the object from the center of Earth.
2. In general, the acceleration due to gravity $\left(g\right)$ on the surface of the Earth is given by,

$g=\frac{GM}{R^2}$, where $G$ is the gravitational constant, $\mathrm{M}$ is the mass of the Earth, and $R$ is the distance of the object from the center of Earth.

Step 2: Explanation

1. Earth is not a perfect sphere, but rather an elliptical sphere. The gravitational acceleration varies at all points on Earth as a result of this distortion, but the mass remains constant since it is independent of the shape.
2. The equatorial radius is 21 km greater than the radius at the poles.
3. The radius of the Earth is maximum at the equator.

Hence, the value of $g$ is minimum at the equator.