A man is sitting on a rotating stool with his arms outstretched. If suddenly he folds his arms the angular velocity of the man would

The scenario is a classic demonstration of the law of conservation of angular momentum. Angular momentum (L) is defined as the product of the moment of inertia (I) and angular velocity (ω), expressed as L = Iω [t1, t7]. In an isolated system where no external torque is applied, the total angular momentum remains constant [t3, t6]. When the man is sitting on a rotating stool and folds his arms inward, he is redistributing his mass closer to the axis of rotation. This action significantly decreases his moment of inertia [t1, t3]. To maintain the constant value of angular momentum (L), the angular velocity must increase proportionally [t2, t6]. This principle is identical to that used by figure skaters who pull their arms in to spin faster [t8, t9]. Consequently, the man's rotational speed increases as his moment of inertia decreases [t5].