পদার্থবিজ্ঞান প্রশ্ন

An airplane is flying on a straight level  course at 200 Km/ hour at a height of 1000 m above the ground. An anti-aircraft gun located on the ground fires a shell with an initial velocity of 300 m/s,  at the instant when the plane  is vertically above it. At what inclination, to the horizontal, should the gun be fired to hit the plane ?