A body weighs less at the equator than at the poles because 1 earth rotates about its axis 2 the ice...........

General Science (Easy) Physics

A body weighs less at the equator than at the poles because:

1. earth rotates about its axis.

2. the ice cap at the poles increases gravitational pull.

3. equatorial diameter is greater than the polar diameter.

4. of some unknown facts.

Which of the statements given above is/are correct?

1 and 2

3 only

1 and 3

4 only

Only statement 3rd is correct.

Acceleration due to gravity (g):

The force of attraction exerted by the earth on a body is called gravitational pull or gravity.
We know that when a force acts on a body, it produces acceleration.
Therefore, a body under the effect of gravitational pull must accelerate.

Acceleration due to gravity at the surface of the earth is given by: g= GM/R2

Where G = Universal gravitational constant, M = mass of the earth, and R = radius of the earth.

EXPLANATION:
As we know, the weight of the body is calculated by the formula

→W = mg
where m - Mass of the body
As Earth is elliptical in shape i.e., it is flattened at the poles and bulged out at the equator, due to which the equatorial radius is about 21 km longer than the polar radius.

As the polar radius is smaller than the equatorial radius, therefore

the acceleration due to gravity is maximum at poles and minimum at the equator. Hence, the body weighs less at the equator than at the poles.
If the earth is rotating, then the effect of rotation of the earth on the value of acceleration due to gravity is maximum at the equator and is minimum at the poles.