Robotic shooting mechanism

See actually my robot is basically a line-follower with a shooting mechanism.It has an on-board mechanism of storing ping pong balls which it has to shoot. My shooting range varies from 3-7 feet(91.4---213.36cm), It has to shoot at 10m/s with a current of 60 A and has 800 turns, length is 20cm and 5 cm diameter and weight 2kg, can anyone of you plz tell me the relation of the Current through the solenoid with the speed of the ball if the mass of the ball is m(2.7 gms) , The general formula wud b gud!!!