The Maths of Spinning Coins and Eulers Disk

A spinning coin rotates as it wobbles. The rate of rotation is (1/cos(θ) - 1) of the rate of wobble. Draw an arrow on a coin and check it yourself!\r
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The notes from the whiteboard are available here:\r
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Here are the videos of the disk spinning:\r
NORMAL SPEED: \r
10% SPEED: \r
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Music by Howard Carter\r
Design by Simon Wright\r
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MATT PARKER: Stand-up Mathematician\r
Website: \r
Maths book: \r
Nerdy maths toys: