Oscillations of a rod pendulum and determination of the acceleration due to gravity on earth - Measuring with rotary motion sensor

In the experiment P1.5.1.3, the oscillation of a rod pendulum, i.e. an simple physical pendulum is investigated. Using the rotary motion sensor S the oscillation of the pendulum is recorded as a function of time. Angle α(t), velocity ω(t) and acceleration a(t) are compared. In addition, the effective length of the pendulum is determined from the measured oscillation period T.
The dependance of the period T on the amplitude A of a oscillation is investigated. For small deflections the oscillation of an pendulum is approximately harmonic and the period is independant from the amplitude. For high deflections this approximation is no longer satisfied: the higher the amplitude is the larger the period.
The rod pendulum is applied as reversible pendulum. The value of the acceleration due to gravity is determined. The pendulum is set up at two pivot points at opposite sides of the rod. The position of two sliding weights influences the period. When the pendulum is properly adjusted, it oscillates on both edges with the same period T. The effective pendulum length l_r corresponds to the distance d between the two pivot points. The acceleration due to gravity is calculated form the effective pendulum length l_r and the period T.