A projectile of mass 2 kg is fired with an initial speed of 111 m/s at an angle of 50? with the horizontal. At the top of its trajectory, the projectile explodes into two fragments of masses 0.8 kg and 1.2 kg . The 1.2 kg fragment lands on the ground directly below the point of explosion 4.2 s after the explosion. The acceleration due to gravity is 9.81 m/s 2 . Find the magnitude of the velocity of the 0.8 kg fragment immediately after the explosion. Answer in units of m/s.