Book: # 5

The object of this experiment is to determine g.  Two small lead balls, each of mass m, are supported on a T-shaped form which is suspended by a fine wire to form a torsion pendulum.  Large lead spheres each of mass M are placed opposite the small balls, exerting a torque on the moving system.  The system is allowed to come to rest, and the equilibrium position is shown by a laser beam reflected to a scale.  The large lead balls are then shifted to give a torque in the opposite direction.  The approach to the new equilibrium is a damped simple harmonic motion and requires over an hour and a half to come to rest.