Question

A man weighs $600N$ on the equator, but when he moves to pole he finds a slight increase in his weight. This is because:

• A. Radius of the Earth is less at poles.
• B. Radius of the Earth is more at poles.
• C. Mass of earth is less concentrated near poles.
• D. The magnetic field is higher at poles than that at the equator.

Answer 1

The correct option is A Radius of the Earth is less at poles.

The Earth is not a perfect sphere. Radius of earth is smaller at poles than at equator.
On Earth, acceleration due to gravity:
$g=\frac{GM}{R^2}$​
where 'G' is the gravitational constant, 'M' is the mass of the earth and 'R' is the radius of the earth.
Hence, the value of 'g' increases at poles.

Weight is the force due to gravity i.e., mg, where 'm' is the mass of the body. Hence, the weight of the body also increases.