|Class 11 Physics Rotational Motion||Angular Momentum In Case of Rotation about a Fixed Axis|
Angular Momentum In Case of Rotation about a Fixed Axis
Example - A child stands at the centre of a turntable with his two arms outstretched. The turntable is set rotating with an angular speed of 40 rev/min. How much is the angular speed of the child if he folds his hands back and thereby reduces his moment of inertia to 2/5 times the initial value? Assume that the turntable rotates without friction.
Solution: When the child folds his hand back, there is no external torque involved, so the angular momentum is conserved in this case.