A 2-kg projectile is fired with an initial speed of 135 m/s at an angle of 68° with the horizontal. At the top of its trajectory, the projectile explodes into two fragments of masses 0.72 kg and 1.28 kg. At 3.8 s after the explosion, the 1.28-kg fragment lands on the ground directly below the point of explosion.
a) Determine the velocity of the 0.72-kg fragment immediately after the explosion.
b) Find the distance between the point of firing and the point at which the 0.72-kg fragment strikes the ground.