Question

If spinning of earth is decreased, weight of the body at poles is

Answer 1

If the earth’s rotation speed increases then the weight of the body decreases.

This is because you see a moving body on the rotating earth’s surface itself is in the reference frame. So when the earth rotates, the centripetal force acts towards the centre of rotation. Also to keep the rotation intact, an equal and opposite centrifugal force acts on the rotating earth.

So if weight of the body = m*g (where g= acceleration due to gravity),

Then under the effect of increased rotational speed of the earth, the equation becomes:

mg’ = mg - centrifugal force

Where g’ = decreased value of acceleration due to gravity. Thus decreasing the weight of the body.

Answer 2

If the earth’s rotation speed increases then the weight of the body decreases.

This is because you see a moving body on the rotating earth’s surface itself is in the reference frame. So when the earth rotates, the centripetal force acts towards the centre of rotation. Also to keep the rotation intact, an equal and opposite centrifugal force acts on the rotating earth.

So if weight of the body = m*g (where g= acceleration due to gravity),

Then under the effect of increased rotational speed of the earth, the equation becomes:

mg’ = mg - centrifugal force

Where g’ = decreased value of acceleration due to gravity. Thus decreasing the weight of the body.