A man is sitting on a rotating table with his arms stretched outwards. When he suddenly folds his arms inside then his:
Correct answer: C. The moment of inertia decreases
- A. Angular velocity will decrease
- B. Angular velocity remains constant
- C. The moment of inertia decreases
- D. Angular momentum increases
Explanation
The moment of inertia is a property of an object that describes how its mass is distributed around an axis of rotation. When the man on the rotating table folds his arms, he reduces the moment of inertia by bringing his mass closer to the axis. According to the conservation of angular momentum, the product of moment of inertia and angular velocity remains constant in the absence of external torque. Therefore, as the moment of inertia decreases, the angular velocity must increase to balance the equation. This is why the correct answer is that the moment of inertia decreases.
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