2. Energy

We put a very small coin right at the top of an object. This

object is a solid sphere. We assume such a coin is frictionless

(no friction with the object) and this object is fixed and has a

radius of R. We push this coin only very little bit and then it

falls by gravity. At what height below the starting point of this

coin will the coin be off the object (without touch with the

object)? Say the starting point is A and the detached point is

B, the question here asks the height difference between A

and B.

Hint 1: Energy conservation.

Hint 2: what is the normal force from the object to the coin?