Explanation:
When the rotational motion of Earth increases, the weight of the body will decrease. This is because the weight of any object is the force exerted on it due to gravity. And the gravitational force depends on two factors: the masses of the two objects and the distance between them.

Effect of Earth's Rotational Motion on Weight of a Body:
When the rotational motion of Earth increases, the distance between the body and the center of the Earth increases. This is because the radius of the Earth is larger at the equator than at the poles due to the centrifugal force. As the distance between the body and the center of the Earth increases, the force of gravity acting on the body decreases.

Proof:
We can prove this using the formula for gravitational force:

F = G * (m1 * m2) / r^2

Where F is the gravitational force, G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between them.

Let's assume that the weight of a body at the equator is W and at the poles is W'. The distance between the body and the center of the Earth at the equator is Re + h, where Re is the radius of the Earth and h is the height of the body above the surface of the Earth. At the poles, the distance between the body and the center of the Earth is Re - h.

Now, we can calculate the ratio of the weight at the equator to the weight at the poles:

W / W' = (G * (Me * m) / (Re + h)^2) / (G * (Me * m) / (Re - h)^2)

Where Me is the mass of the Earth and m is the mass of the body.

Simplifying this expression, we get:

W / W' = (Re - h)^2 / (Re + h)^2

As we can see, the value of W/W' is less than 1, which means that the weight of the body is less at the equator than at the poles.

Conclusion:
Therefore, we can conclude that if the rotational motion of Earth increases, the weight of the body will decrease due to the increase in the distance between the body and the center of the Earth.

Will decrease