If the gray cannon is fired just as the monkey (red ball) is dropped, and we aim right at the monkey, we'll always hit it. This is independent of the launch speed of the cannon ball. Faster speeds will hit the monkey sooner than slower ones, but they will always hit. (Hitting the ground first isn't a key part of the problem--do it all high enough so the ground isn't in the way---the cannon ball will always hit the monkey).
Hunter and Monkey
Grade Level Grades 6-12