Human Gyroscope, 1Q50.15

Topic and Concept:

• Rotational Dynamics, [:RotationalDynamics#Gyros: 1Q40. Gyroscopic Motion]

Location:

• Cabinet: [:MechanicsCabinet:Mechanic (ME)]

• Bay: [:MechanicsCabinetBayB9:(B9)] & [:MechanicsCabinetBayB12:(B12)]

• Shelf: #1

attachment:RotatingPlatform-03-400.jpg

Description:

One stands on a rotating platform and with a spinning bicycle wheel, rotate the bicycle wheel so that it transfer some of it's energy to the rotating platform.

Important Setup Notes:

• Demonstration may require practice.
• A volunteer may be required.

Setup and Demonstration:

1. Set Rotating Platform out on the floor.
2. Level the platform.
3. Get the wheel spinning by grasping a handle (the axle) with one hand. Then, grabbing the outer rim with the other hand, apply a strong, tangential force.
4. Hand off the spinning wheel to the volunteer (you should still be holding on to the axle) having him or her hold onto the axle with both hands, one on either side. Tell him or her to keep his or her arms straight so as not to bump and thereby slow down the spinning wheel.
5. (Finish!)

Cautions, Warnings, or Safety Concerns:

• Fingers, long hair, and necklaces may get caught in the spooks of the moving bicycle wheel. Take precautions!
• Due to the high rotational speed of the bicycle wheel, stopping the wheel can be difficult.
• The volunteer may get dizzy from spinning.

Discussion: (FIX!) First have the volunteer raise the bicycle wheel vertically over there head, with the wheel not spinning and then with it spinning. The volunteer must hold the spinning bicycle wheel by the ends of its axle horizontally at arms length. Have the bicycle wheel spun up to high speed by hand and give it to either the instructor or a volunteer or whomever is standing on the rotating platform.

Again have them hold the bicycle wheel firmly by its handles while standing on a rotating platform to help illustrate Newton's third law (action and reaction) and the conservation of angular momentum. One can sit on a stool that is placed on the rotating platform as well.

The person now can rotate one direction or the other by turning the axis of the bicycle wheel in different directions. For best results, orientate the spinning bicycle wheel's axis perpendicular to it original direction, so that it is vertical or parallel to the rotational axis of the platform. This well transfer the most angular momentum to the rotating platform to make the platform and person rotate the opposite direction of the spinning bicycle wheel.

References:

• [http://sprott.physics.wisc.edu/demobook/chapter1.htm demobook/chapter1]

• [http://sprott.physics.wisc.edu/demobook/uwpress.htm Physics Demonstrations]

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