A) The army has acquired radar that can track an artillery shell in flight and determine its origin before it hits. The system erects a sensitive electronic plane over a broad area and can detect any projectile piercing that plane. After tracking the shell and plotting its path, system's computer back tracks the trajectory to the firing location. The enemy has fired a shell at the radar station. The radar detects the shell at the coordinates (400 m, 75 m) and again at (200 m, 50 m). Given that the path of a projectile projected near the surface of the earth is a parabolic, determine (i) the angle of projection of the shell and (ii) the initial velocity of projection.