Demos: 1Q-32 Stability Under Rotation


A phonograph record is suspended by a cord through its center hole. A ball bearing swivel allows the record to be spun without twisting the cord. If the record is swung back and forth without spinning, it tends to “flop” around randomly. However, if the record is given a spin, the axis will maintain its direction in space as the record is swung back and forth, illustrating gyroscopic stability.

Directions: Hold the cord in one hand and swing the record back and forth, showing the randomness of its movement. Then grasp the edge, give it a good spin and swing the record back and forth.

Suggestions for Presentation: Focus on the idea that the torques about the center of rotation are zero, so the angular momentum vector cannot change.

Applications: Stability of spinning rifle bullets and footballs, as well as the standard gyroscope.

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Last Updated: May 9, 2016 11:44 AM