1Q60.81 - Dynamic Balancing
Mount the clamps opposite each other on the same side ( front side ) of the rim. Note how the wheel spins smoothly when rotating rapidly. ( You will probably have to move one of the clamps right or left slightly to achieve a good balance. ) Now move only one of the clamps to the other side ( rear side ) of the wheel. While the static balance still remains, the axle will shake violently when spun because of poor dynamic balance.
The "cross" unit with bearings works very well. Change the dynamic balance parameters by moving the rod to any of the straight or diagonal holes.
The wooden and nylon demos show a precession about the axis of rotation. Hold them so that one end of the axle is in each hand. Throw into the air and at the same time spin the demo about the axis. The demo will process as it spins and falls through the air.
- Clifton Bob Clark, Stuart Thompson, "Dynamical Balance and the Rotating Rod - A Personal Demonstration", TPT, Vol. 26, # 4, April 1988, p. 237.
- M- 720: "Wheel With Weights-Assym. Rotator", DICK and RAE Physics Demo Notebook.
- Jearl Walker, 1.176, "Balancing a Tire", The Flying Circus of Physics", p. 78.
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