Explanation:

When a man is sitting on a rotating table with his arms stretched outwards, his moment of inertia is high. The moment of inertia depends on the distribution of mass and the distance of the mass from the axis of rotation. When the man folds his arms inside, the distance of mass from the axis of rotation decreases, leading to a decrease in moment of inertia.

Moment of Inertia:

Moment of inertia is the measure of an object's resistance to rotational motion. It depends on the mass of the object and the distance of the mass from the axis of rotation. The moment of inertia is given by the formula I = mr^2, where m is the mass of the object and r is the distance of the mass from the axis of rotation.

Effect of Folding Arms:

When the man folds his arms inside, the distance of mass from the axis of rotation decreases, leading to a decrease in moment of inertia. This is because the mass is now closer to the axis of rotation, reducing the resistance to rotational motion.

Angular Velocity and Momentum:

The angular velocity of the rotating table is the same before and after the man folds his arms inside. This is because the angular velocity depends on the speed of rotation and the distance of the object from the axis of rotation. The speed of rotation remains constant, and the distance of the man from the axis of rotation also remains constant.

Similarly, the angular momentum of the rotating table is conserved. Angular momentum is the product of moment of inertia and angular velocity. When the moment of inertia decreases, the angular velocity increases to conserve the angular momentum. However, since the speed of rotation remains constant, the increase in angular velocity is negligible.

Conclusion:

When a man sitting on a rotating table folds his arms inside, the moment of inertia decreases, leading to a decrease in resistance to rotational motion. However, the angular velocity and angular momentum remain constant since the speed of rotation remains constant.