TM-1302 Inertia In Rotational Motion Apparatus


  • 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.



  • 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


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 the wall mounted stands; it is ideally suited to group work for 2-3 persons.