Why doesn't a spinning coin flip over?

  • Thread starter hihiip201
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  • #1
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Main Question or Discussion Point

As titled:


I would be satisfied with a qualitative explanation(pure physical), but it would be nice if someone can also provide the mathematical model.



thanks
 

Answers and Replies

  • #2
Drakkith
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Are you asking why it doesn't stop spinning and flop over onto one of its sides? Just not sure what you mean by "flip over".
 
  • #3
ehild
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Remember conservation of angular momentum.

ehild
 
  • #4
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Are you asking why it doesn't stop spinning and flop over onto one of its sides? Just not sure what you mean by "flip over".


oh sorry I should be more clear.

I meant why doesn't it fall down on the ground(flat) as a stationary coin would.
 
  • #5
Drakkith
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  • #6
clem
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It follows from Euler's equations. If there is an Omega_z (z is the axis of the coin), and I_z is larger than I_x and I_y, Omega_x and Omega_y follow SHO, and oscillate without flipping over.
You can win money with that, just don't get caught.
 

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