Centripetal force is needed to keep things moving in a circle. And why dont they want to? THEY JUST WANT TO GO IN A STRAIGHT LINE. REALLY. THATS ALL EVERYTHING WANTS TO DO.

P.S. If you have a masters degree or PhD in physics and would like to talk to me about rotating reference frames, Id love to. But this is not the right context. This videos purpose is to demonstrate inertia in inertial reference frames. You know, the ones where Newtons Laws apply. Yeah, those. Certainly youll agree that inertia is of the greatest conceptual importance. As a teacher, I have found that most people I meet do not have a conceptual understanding of inertia though they are able to recite Newtons First Law in a droning voice when asked. Words with no meaning. Blech.

BTW — Those who like accelerated reference frames and their challenges may enjoy this video about impending motion of rigid solids:
www.youtube.com/watch?v=JLHVf3eJKak
I made it. Maybe you like watching physics videos in your spare time.

And I will SORTA agree with you if you claim that theres a centrifugal force on the wood ring (as a 3rd-law counterpart to the centripetal force on the ball). I like Newtons 3rd as much as the next guy, but youre creating a REALLY shady definition. If we had no friction, the ring wouldnt even be moving. How you gonna define «center fleeing» for something that is not only not going in a circle...its not moving at all??!@?#$%?^$#?%$# But thats just a technical complaint. Really, I am just trying to convince early physics students that the BALL feels no outward force. Cuz trust me, THEY THINK IT DOES. Ask your mom — she may even think the ball feels an outward force. My people often predict that the balls path will curve OUTWARD from the circle. Thats what Im really trying to cure here. Love you, though! Keep warm this winter!