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I am referring to this:

Within a week I was in the cafeteria and some guy, fooling around, throws a plate in the air. As the plate went up in the air I saw it wobble, and I noticed the red medallion of Cornell on the plate going around. It was pretty obvious to me that the medallion went around faster than the wobbling.

I had nothing to do, so I start to figure out the motion of the rotating plate. I discover that when the angle is very slight, the medallion rotates twice as fast as the wobble rate - two to one. It came out of a complicated equation! Then I thought, ``Is there some way I can see in a more fundamental way, by looking at the forces or the dynamics, why it's two to one?''

I don't remember how I did it, but I ultimately worked out what the motion of the mass particles is, and how all the accelerations balance to make it come out two to one.

Anyone knows how to derive the two-to-one relationship?

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1 Answer 1

up vote 5 down vote accepted

Take a look at this article. The authors present an elementary explanation for the two-to-one ratio of wobble to spin frequencies.

UPDATE: In case you don't have easy access to the AJP, here it is: article.

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