Situation: There is a big ball that never moves, and a small ball on it.
If we let the small ball roll down from the big ball, what is the angle that between the top of the big ball and the place that the small ball leaves the surface of the big ball?
Or do we need more information about situation?
Maybe equation about circular motion?
The Attempt at a Solution
I tried to let R=0 to my calculations but I found out that the angle=0