This apparatus enables experiments to be performed on rotational motion in general. Weights can be fitted to a rotating rod at marked distances from the centre. A dumbbell-shaped arrangement is thus created; the inertia properties of this arrangement can be changed easily and recalculated. The arrangement is fitted to a low friction ball bearing mounted rotating drum. The system is accelerated by a metal weight attached to a cord wrapped around the drum. The time taken for the weight to fall is measured using a stopwatch, the moment of inertia of the object can then be determined. The experiment is set up quickly using table clamps and stands; it is ideally suited to group work for 2-3 persons.
Learning Objectives / Experiments
- Explanation of the term "moment of inertia" - Determination of the moment of inertia of various bodies - Influence of the rotating mass on the moment of inertia - Influence of the radius of rotation on the moment of inertia - Comparison of the moments of inertia of solid and hollow cylinders of
the same weight and outside diameter
* Comparison of the moments of inertia of different
 Student experiments on moments of inertia, comparison of the inertia of rotation of various bodies  Metal rotating bar, weights with knurled bolts for quick fastening  Solid and hollow test cylinders  Ball bearing mounted rotating drum, anodised aluminium  Acceleration of system by weight attached to the drum