Physics Practical Aim:Investigate the factors which determine the damping of a compound pendulum to find an equation that relates the amplitude of oscillations to the factors chosen to investigate. Compound Pendulum ===== For a system to oscillate in simple harmonic motion there are 3 conditions which should be satisfied; 1. A mass that oscillates, 2. A central point where the mass is in equilibrium, 3. A restoring force which returns the mass to its central point. The compound pendulum (shown above) clearly does oscillate with S.H.M as there is a mass that oscillates (1) about an equilibrium point (2) and a restoring force returning it to its central point (weight of the mass / tension in ruler (3)). In S.H.M, there is a constant interchange between kinetic and potential energy. In the case of the compound pendulum the potential energy is provided by the increase in gravitational potential energy (mgDh) as the oscillations occur in a circular fashion taking the mass higher above the ground at its maximum / minimum displacements. So in an ideal situation (one where 100% of the DEp is converted to kinetic energy) the oscillations should go on forever with constant maximum / minimum amplitudes.