The Hardest Exam I Ever Took at MIT in Physics

When I studied, I had  subject of Physics but I was not studying Physics, the lecturer asked a question by describing it.

It was like this. There is a disc that is rotating and in one moment a chunk of this disc is cut from the disc.
What would happen to the disc?

No other student had a reply, and I replied. Once the disc losses a chunk of its mass, the equilibrium is ruined so the rotation is disrupted. This is due to the fact the mass should be equal in all sides of the disc. And I passed that exam