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 Photographing the locus of a pendulum |  | 
- Pendulum
Weight: a penlight hung facing up Length: 90cm The pendulum was hung above the center of a rotating table.
- Photography
- The laboratory was made dark, and using long exposure, the locus of the pendulum was photographed with a camera set on the rotating table.
- Experimental Process
- The penlight was turned on, and swung in a straight line from the point of view of outside the rotating system.
