a ball is thrown horizontally off a cliff 18.2 m/s and hits the ground 30.9 m from the base of the
cliff. how high is the clift?

14 m

Explanation:

This situation is related to parabolic motion and can be solved by the following equations:

(1)

(2)

Where:

is the horizontal distance travelled by the ball

is the ball's initial velocity

is the angle (it was thrown horizontally)

is the time

is the ball's final height

is the ball's initial height and the cliff height as well

is the acceleration due gravity

Let's begin by finding from (1):

(3)

(4)

(5)

Isolating from (2):

(6)

Substituting (5) in (6):

(7)

Finally: