TEL-RP6010

Kater Precision Pendulum

-Pendulum Rotating about axis '2'

-Measure g to a few parts per thousand in less than ten minutes.

-Measure g to a few parts in ten thousand in one lab period.

-Take data with a photogate or a stopwatch.

Finally a Kater Pendulum has been designed to allow a measurement of g to within a few parts per thousand in about 10 minutes. In addition, a very precise measurement of g (to within a few parts in ten thousand) can be performed in a single lab period.

The axes of rotation are by means of a “knife edge” which is inserted through one or the other of two holes; whose placement in the pendulum were carefully chosen. Although period measurements may be made with a stopwatch, a photogate is preferred to: (i) eliminate large reaction time errors, and (ii) insure that data is collected in an amplitude regime that is essentially isochronous.

A quick method operates with a single mass configuration of the pendulum. The period of swing about each axis is measured and g can be determined by using:

Although the errors of this “quick” method are about 5 times larger than those of the more precise method; the total time for data collection and analysis is correspondingly reduced.

The more precise method collects a different T1 and T2 for each of several positions of a small slider whose mass is approximately 2% of the mass of the pendulum. By performing a regression analysis on the graphs of T1 and T2 as a function of slider position, the position for which T1 = T2 = T can be determined and g calculated from:

Apparatus Includes:

-Precision cut and drilled brass rod

-clamp with knife-edge

-lab manual with all equations derived

-detailed instructions for performing the experiment