1. The problem statement, all variables and given/known data A Person sitting firmly over a rotating stool has his arms stretched. If he fold his arms, his angular momentum about the axis of rotation : A.) Increases B.) Decreases C.) Remains Unchanged D.) doubles 2. Relevant equations Conservation of Angular Momentum 3. The attempt at a solution Since External Torque =0 Then final angular momentum = initial angular momentum => (C.) But I wanted to further ask that in the Equation L=I*(omega) since L has to be constant(if external torque = 0) then: If I increases then omega decreases to keep L constant or if omega increases then I decreases to keep constant Will folding his arms increase I( Moment of Inertia ) or decrease it??