PURPOSE: To demonstrat centripetal force and centrifugal reaction in a dramatic way.

DESCRIPTION: Balance the penny (face up) on the flattened coat hanger tip, as shown in the photograph. Start slowly swinging the hanger back and forth like a pendulum, then rotate it in a complete circle. With practice, it is possible to rotate the system several times and stop the motion without dislodging the penny.

SUGGESTIONS:

REFERENCES:

EQUIPMENT: Bent coat hanger with flattened end, penny.

SETUP TIME: None.

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