93 seconds you’ll never get back

Remember Leonhard Euler from the Satan’s Arithmetic post? Of course you do.
Now behold Euler’s Disc – probably the most hypnotic thing ever.

Look into the eyes, look into the eyes, not around the eyes… and you’re under…

The physics behind this “scientific toy” can be found here, but basically, it comes down to this:

A spinning/rolling disk ultimately comes to rest; and it does so quite abruptly, the final stage of motion being accompanied by a whirring sound of rapidly increasing frequency. As the disk rolls, the point P of rolling contact describes a circle that oscillates with a constant angular velocity w. If the motion is non-dissipative, w is constant and the motion persists forever, contrary to observation (since w is not constant in real life situations). In fact, precession rate of the axis of symmetry approaches a finite-time singularity modeled by a power law with exponent approximately -1/3 (depending on specific conditions).

So there you have it. Obviously,  it’s important that you remember that rolling friction is the primary mechanism for kinetic energy dissipation in this scenario and not air resistance.

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