Precessing Toy Gyroscope, 1Q50.51

Topic and Concept:

• Rotational Dynamics, 1Q50. Gyroscopic Motion

Location:

• Cabinet: Mechanic (ME)

• Bay: (A12)

• Shelf: #1

Abstract:

A pull string gyroscope precesses around an axis.

Important Setup Notes:

• This demo may require practice.

Setup and Procedure:

1. Place the stand on a table.
2. Locate a small hole on the axle of the gyroscope. Take one end of the black string, and feed it through the hole about an inch.
3. Neatly wind up the string around the axle.
4. Now place the gyroscope on the stand so that the axle is vertical. Press down with a finger on the top "ball" to keep the gyroscope in place.
5. With your free hand, grab the string and give it a continuous pull until the string is completely out.
6. You can now release the gyroscope. It will begin to precess due to the torque of gravity.

Cautions, Warnings, or Safety Concerns:

• N/A

Discussion:

Once the wheel is spinning, it has angular momentum. The amount can be increased by making the wheel spin faster. Since angular momentum is conserved, the rotational axis of the wheel will remain in place. This would be the case if there were not any torques acting on the wheel. In our case, this net torque is due to the gravity. The resultant effect is that our wheel precesses around the original axis.

Videos:

• Lecture Demonstration's Youtube Channel

References:

• Wikipedia - Gyroscope

• Wikipedia - Angular Momentum

• Wikipedia - Nutation

• Wikipedia - Precession

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