Two identical discs are initially at rest in contact on a horizontal table. A third disc of same mass but of double radius strikes them symmetrically and comes to rest after the impact.
(a) Find the coefficient of restitution for the impact.
(b) Find the minimun kinetic energy of the system (as a percentage of original kinetic energy before collision) during the process of collision.
Treat the collision to be instantaneous

Answer

(a) `(9)/(16)`
(b) 36 %