Center of Mass: Rubber Cork Bolas
Safety Warnings
Warning: UV Light Exposure
Purpose
Two unequal rubber stoppers connected by rope are tossed through a UV beam in a dark room. The stoppers trace complex curves, but a fluorescent tape marking the center of mass follows a simple parabola — demonstrating that internal forces cannot change the CM trajectory.
Figure 1:
The bolas: two unequal rubber stoppers connected by rope, with fluorescent pink tape marking the center of mass.
Figure 2:
Verifying the center of mass by balancing the bolas on a meter stick supported by a semicircular wooden pivot. The fluorescent tape sits at the balance point.
Equipment
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Demo Apparatus
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