Oscillations and Waves > Oscillations > Pendula
DCS# 3A15.70

KATER'S PENDULUM

kater's pendulum

APPARATUS
Kater's pendulum
101-13-F
stopwatch
101-05-D4


DESCRIPTION
This is a reversible physical pendulum with adjustable weights.   It can be used to determine the value of g more precisely than is possible with a simple pendulum, because its effective length can be measured more precisely.

Adjust the positions of the masses so the period of oscillation is the same in either orientation.  It can be shown that the period is the same as that of a simple pendulum whose length is equal to the distance between the two pivot points.   So g = (2π/T)2L.
NOTES

Make sure the support is clean and level so the pendulum oscillates about a horizontal axis.  Be careful not to nick the knife edges.

Don't move the masses without marking where they were.

The distance between the two knife edges is 94.52 +/- 0.01 cm.

The value of g in Oberlin is 9.80196 +/- 0.00003 m/s2 according to the National Geodetic Survey website: http://www.ngs.noaa.gov/cgi-bin/grav_pdx.prl.

REFERENCE

TPT 28, 291 (1990)