Air Track - Center Of Mass Pendulum
To show uniform motion of the center of mass of a vibrating pendulum/glider system.
Air track with center of mass glider, as photographed.
Use black light to illuminate the center of mass in the large lecture halls.
A symmetric (balanced) pendulum is suspended from an air track glider. The mass of the pendulum bob is approximately the same as that of the glider, so the center of mass (marked by a fluorescent disc) is approximately at the midpoint of the rod between the bob and the center of the glider. When the pendulum oscillates, the center of mass moves uniformly in the horizontal direction or remains motionless (horizontally).