PURPOSE: To demonstrate that the system is stable until the combined center of gravity moves beyond the end of the lecture table.

DESCRIPTION: Walk the plank slowly, until the system becomes unstable. Table clamps on either side of the plank prevent sideways motion. A cinder block loosely tied to the far end of the plank limits the tilt of the plank in case you walk too far.

SUGGESTIONS: Try not to think about the sharks.

REFERENCES: (PIRA 1J40.24)

EQUIPMENT: Heavy (28 kg) wooden plank, two table clamps, cinder block with rope, and sharks.

SETUP TIME: 5 minutes