A ball is thrown horizontally from a cliff at a speed of 15 m/s and strikes the ground 45 meters from the base of the cliff. How high was the cliff (rounded to the nearest meter)

Answer 1

it took the ball 45/15=3 seconds to travel 45 m horizontally

In those 3 seconds, it fell 4.9*3^2 = 44.1m, the height of the cliff