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Kater's Reversible Pendulum

The Experiment of Kater's Reversible Pendulum contains not only the principle basis of the pendulum, but also the concept of the angular moment of inertia of a rigid body, as well as the understanding of how to derive from a compound pendulum the relationship among the swing period, the amplitude, the angular moment of inertia, and the acceleration of gravity. The purpose of the experiment of Kater's reversible pendulum is to study characteristics of a compound pendulum and to measure the magnitude of the acceleration of gravity g from the Kater's reversible pendulum (a compound pendulum). In this device, on each side of the center of mass of the pendulum contains a knife-edge fixed in place. During the experiment, change the position of the metallic mass, trying to find the position when the two periods of the pendulum swinging about the two knife-edges are equal, to calculate the magnitude of the acceleration of gravity.















Two knife-edge pivot points and two adjustable masses are positioned on the rod so that the periodic time of swing is the same from either edge.

Metallic Masses
The center of mass of the reversible pendulum can be controlled by adjusting the position of the metallic masses.

Support Holder
Balance the reversible pendulum on a suitable fulcrum along each of its axies to find the center of mass.

8748 Timer and Infrared Sensor
Stick a reflective tape to the pendulum
and detect the number of swings using
Infrared sensor. Therefore the periodic
time of the pendulum can be determined.


 Kater's Reversible Pendulum


Department of Physics (Digital Archive Project of NTU General Physics Laboratory)
National Taiwan University