0g ball is fired horizontally with initial speed toward a 110 g ball that is hanging motionless from a 1.10 m-long string.

A 36.0g ball is fired horizontally with initial speed toward a 110 g ball that is hanging motionless from a 1.10 m-long string. The balls undergo a head-on, perfectly elastic collision, after which the 110 g ball swings out to a maximum angle = 52.0 degrees, what is the velocity