| 6.3.2.1.2. | The centre of percussion of the pendulum coincides with the centre of the sphere, which forms the hammer. It is at a distance l from the axis of oscillation in the release plane, which is equal to 1 m ± 5 mm. The reduced mass of the pendulum is mo = 6.8 ± 0.05 kilograms. The relationship of mo to the total mass m of the pendulum and to the distance d between the centre of gravity of the pendulum and its axis of rotation is expressed in the equation: | a0c0 |