UNTRANSLATED .. 6.2

Angular Velocity of Pendulum

Objective

To study the nature of oscillations of a pendulum. An angle encoder is required for measuring the angular displacement as a function of time. But using a DC motor as a sensor, we can measure the angular velocity as a function of time.begin_inset Separator latexparend_inset

_images/pendulum-screen.png

Procedure

Discussion

The observed waveform is shown in figure. Fitting it with equation A = A_0 \sin(\omega t + \theta) \exp( − Dt) + C, using Grace gave an angular frequency of 10~Hz.

The pendulum should be made with a heavy bob and a light weight rod connecting it to the axis of the motor. In this case, the DC motor acts like a generator and the voltage is proportional to the instantaneous angular velocity.