A fidget fidget spinner is a toy that you can set spinning b holding the centre between two fingers and giving the rim a push.
When the fidget spinner starts to spin, it has angular momentum, with magnitude given by
\[J= \omega I\]
, directed perpendicular to the plane of the spinner.
Just like linear momentum, angular momentum requires a force to change, in either magnitude or direction. And that is why fidget spinners are so much fun to play with.
