| 
 Photographing the locus of a pendulum |  | 
|   Period of rotation:  |   Period of rotation:  |   Period of rotation:  |   Period of rotation:  |   Period of rotation:  | 
|   | When the period of rotation and the
    pendulum's oscillation period coincide, the pendulum starts moving in a circular fashion. This is called inertial oscillation. | 
Experimental conditions
The oscillation period of the pendulum was
1.8 sec.
N is the period of the rotation expressed as a multiple of the period of the pendulum.Photographic conditions
f=50mm, F3.5, Bulb, ASA100, ND filter used.