To demonstrate coupled translational - rotational oscillations.
- Wilburforce pendulum
- Retort stand
A helical spring has a "bob" with an adjustable moment of inertia. This has been chosen such that the period of rotation is equal to the S.H.M. period of the simple pendulum. On displacing the bob vertically the device starts like a simple mass on a spring, but the torsional motion increases with each oscillation until the motion is purely rotational. The device then cycles between the two modes of operation.