But, what if you're not rigid? Remember that word rigid in Newton's first law of rotational motion. Why was the
word rigid in there? It's because if you're not rigid, you can change your rotational mass. You can't change your
ordinary mass. That's really, really, really fixed, but you can change your rotational mass by changing your shape.
And if you do that, Newton's first law of rotational motion no longer applies to you. And what’s more, you do
experience changes in angular velocity, for a good reason. So I'll isolate myself again into some separate from the
whole world and now my angular momentum is constant because it's conserved and I can't exchange it with
anything. And my rotational mass is constant because I'm playing at being rigid. So therefore my angular velocity is
constant. It's coming along for the ride.