the horizontal speed is constant.
So, how long does it take to fall 36 meters?
h(t) = 36 - 4.9t^2
As to the distance of the boat, it depends on the goal: hit or no hit?
a canon is shot horizontally at 15 m/s off a cliff, which is 36m above water. how far away from the cliff should the target enemy boat be when the canon is shot?
2 answers
The goal is to hit I believe.