A projectile of mass 20.0 kg is fired at an angle of 55.0 to the horizontal with an initial velocity of 350 m/s. At the highest point of the trajectory the projectile explodes into two equal fragments, one of which falls vertically downwards with no initial velocity immediately after the explosion. Neglect the effect of air resistance: (i) How long after firing does the explosion occur? (ii) Relative to the firing point, where do the two fragments hit the ground? (iii) How much energy is released in the explosion?