Question

A ball is thrown horizontally from a cliff at a speed of 15 MS and strikes the ground 45 m from the base of the cliff how long was the ball in the air

Answer 1

Answer: 3s

Explanation: initial horizontal velocity of 15m/s is independent of the acceleration due to gravity, therefore, a=0

S= it +1/2at2

45=15*t +1/2*0*t

45=15t

t=45/15

t=3s

Answer 2

We don't need to know about the cliff.

If the ball was thrown horizontally at 15 m/s and hit the ground 45 meters away, then it had to be sailing for (45 m) / (15 m/s) = 3 seconds in order to cover that distance.