Rotational inertia device: Sliding weights on rotating rod.

Rotational Inertia Device. Two equal masses slide on a horizontal bar which can rotate freely on its vertical axis. A swivelled knob is attached to the 2 masses via a cord which passes over 2 pulleys in the axis of rotation. By pulling upward on the knob, one can vary the distance of the masses from the axis of rotation, thereby changing the moment of inertia of the system. As the masses are pulled inward, the angular velocity increases greatly. When the masses slide outward, the angular velocity suddenly drops. The masses are 150 gm. each. The horizontal bar has a total length of 45 cm. Swivel knob has ball bearings to reduce friction. CONSERVATION OF ANGULAR MOMENTUM.