Imagine that you want to shoot an apple hanging in a branch with an arrow. You aim the arrow and at the exact time you shoot it, the apple falls from the branch. Will it hit? It should still hit the apple if the air resistance ( wind) is negligible that day. Why will the projectile always hit the falling object it is aimed at if it is fired at the same time the object starts to fall? Think about this problem in terms of projectile motion.