A spinning cap that reverses direction?

AI Thread Summary
The discussion centers on a rattleback toy, which spins and reverses direction due to its unique shape and the physics involved. When the rattleback is spun, it initially moves in one direction but, due to the distribution of mass and the effects of friction and torque, it eventually comes to a stop and then reverses direction. This reversal occurs because the toy's design creates a shift in angular momentum when it slows down, allowing it to gain a new rotational direction. The mechanics of this phenomenon are complex and involve principles of angular momentum and energy transfer. Understanding the rattleback provides insight into interesting physical concepts and their applications.
kyin01
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I was watching a video on where this guy spins a a dial or capsule or a cap (I couldn't really tell, but it was like a long thing cylinder capsule look a like) and well he gave it a quick push and the cap came to a stop and than reverses direction.

What could cause this?


I know that angular momentum is not conserved because of external torque (gravity) and friction causes the thing to come to a halt, but why would it reverse direction. Where does it get the force to reverse direction?
 
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