KEAM 2019 Physics and Chemistry Paper

A spring of natural length l and spring constant 50 N/m is kept on a horizontal frictionless table with one end attached to a rigid support. First the spring was compressed by 10 cm and then released to hit a ball of mass 20 g kept at a distance l from the rigid support. if after hitting the ball, the natural length of the spring is restored, what is the speed with which the ball moved? (Ignore the air resistance)