A kid of mass 50 kg stands at the edge of a platform of radius 1 m which can be freely rotated about its axis. The moment of inertia of the platform is 0.02 kg-m2. The system is at rest. The kid throws a ball of mass 2 kg horizontally to his friend (friend standing on the ground) in a direction tangential to the rim with a speed 10 m/s as seen by his friend. The angular velocity with which the platform will start rotating in rad/s is