Torque-Free Precession and Wobble direction

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Discussion Overview

The discussion revolves around the concept of torque-free precession, specifically focusing on the wobble direction of a spinning plate and its relationship to the spin direction. Participants explore whether the wobble can occur in the same direction as the spin or in the opposite direction, and how this might change based on the initial conditions of the spin.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions if the wobble direction can be either in the spin direction or retrograde, depending on whether the plate is tossed upward or downward.
  • Another participant references Feynman's observations about the wobble frequency being half the spin rate, while also noting a potential contradiction with the equation suggesting two wobbles per spin.
  • There is a discussion about the wobble to spin ratio being influenced by the size and shape of the plate, with a mention of limitations when the amplitude of the wobble is too large.
  • Some participants assert that Feynman's Wobbling Plate is a special case of the Euler top.
  • A question is raised about the differences between torque-free precession and pure precession, specifically regarding the wobble and spin ratios.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between wobble and spin direction, and there is no consensus on the implications of Feynman's observations or the effects of amplitude on wobble behavior.

Contextual Notes

Participants mention the need for clarity on definitions and conditions under which the wobble behavior is analyzed, particularly regarding the amplitude of the wobble and its effects on the observed ratios.

Dueschnozzle
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In Torque-Free Precession of a plate, can the direction of the Wobble be either in the spin direction or retrograde to it?

For instance if you tossed the plate upward vs downward with the same spin direction. Would the wobble direction and frequency be inverse?
 
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Anyone?
 
I am not sure that understood your question correctly, but anyway you are asking about the Euler top. Try textbooks
 
wrobel said:
I am not sure that understood your question correctly, but anyway you are asking about the Euler top. Try textbooks
Hmm... I was asking more about Feynman's Wobbling Plate. Feynman said he observed the wobble at half the spin rate, but his equation says it's 2 wobbles per spin. Could both be true? From what I've read the wobble to spin ratio is determined by the size and shape, with the caveat as long as the amplitude is not too large. What happens when the amplitude is too large?
 
Dueschnozzle said:
I was asking more about Feynman's Wobbling Plate.
yes, it is a special case of the Euler top
 
wrobel said:
yes, it is a special case of the Euler top
So is this the difference between torque free precession = 2 wobble/1retrograde spin, vs roll or pure precession = 1wobble/1spin in same direction or zero spin?
 

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