fuckyeahphysica:

The simple physics behind a Fidget Spinner

When you want something to spin for a really long time you need to make sure that the friction does not slow it down.

And
we can do this by adopting ball bearings. This is so because friction offered due to rolling is much smaller than due to sliding.

And many Fidget spinners indeed use ceramic ball bearings to keep them spinning for a long time. **

Mass Distribution

The next most crucial component is the Angular Momentum. Angular momentum is equal to the product of rotational velocity and the
moment of inertia. 

And by distributing more mass towards the edge, the fidget spinner gains high moment of inertia keeping it spinning longer. 

That’s why the spinners have that weird peculiar shape.

But, Why do they feel alive ?

The angular momentum of a fidget spinner happens to point outwards from
the spinner’s center.

And so to change the direction of the momentum —
rotating the spinner with your fingers — you must apply a force. You
push on the spinner, and the spinner pushes back on you.

That’s why a
fidget spinner feels like it fights you, like it’s alive.

– Nerdist

A very fascinating toy nevertheless!

** Spin Test : Ceramic Vs Steel ball bearings

*** Fidget spinner trick shots

Fidget Spinners and Rolling Shutter

@smartereveryday​ in his recent video goes on to explain the physics behind why some fidget spinners look like something out of a samurai movie.

Its absolutely beautiful! Do check it out.

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