Question

Force of gravity is least at:

• A. The equator
• B. The poles
• C. A point in between equator and any pole
• D. None of these

Answer 1

The correct option is A

The equator

Explanation for correct option:

In case of option $\left(A\right)$,

1. The shape of the earth is an ellipse where the equator is on the extended side of the ellipse.
2. Hence, the equator is at a greater distance from the center of the earth compared to other points on the earth.
3. We know that gravitational force is inversely proportional to the distance between the two bodies.
4. If $G$ is the universal gravitational constant, $M$ is the mass of the earth, $R$ is the distance from the center of the earth to the surface of the earth, $m$ be the mass of the body, the gravitational force acting on the body at the equator is given as $F=\frac{GMm}{R^2}$
5. We know that $R$ of the equator is greater than $R$ of the poles.
6. Hence, $F$ on the equator is less than $F$ on the poles.
7. Therefore, the force of gravity is least at the equator.

Explanation for incorrect option:

In case of option $\left(B\right)$,

1. The poles are at a shorter distance from the center of the earth compared to other points on the earth.
2. We know that gravitational force is inversely proportional to the distance between the two bodies.
3. Therefore, the force of gravity is maximum at the poles.

In case of option $\left(C\right)$,

1. A point in between the equator and the poles are at a shorter distance from the center of the earth compared to the equator.
2. We know that gravitational force is inversely proportional to the distance between the two bodies.
3. Therefore, the force of gravity is more at a point between the equator and the poles compared to the equator.

In case of option $\left(D\right)$,

1. Since we have already established a correct answer, this option is not applicable.

Hence, option $\left(A\right)$ is the correct answer.