We shall take as working example the experiment of the free oscillations in a pendulum.

Basic data

The basic data for this experiment, in adequate units, are:

Measurement of the free Period

For measuring the Period (1/frequency) of this system we started from a small amplitude situation, set the velocity of the mass to zero, and switch on the clock. Then we measured the elapsed time for three full oscillations (checking the inversion in sign of the x-component of the velocity of the particle):
The result we measured was:

Checking the results:

Theoretical period for small amplitude oscillations is:
(approximately 2*1.5*p).