Question

A rock is dropped from a sea cliff and the sound of it striking the ocean is heard 3.7 s later. If the speed of sound is 340 m/s, how high in meters is the cliff?

Answer 1

Let H be the height of the cliff. The time to hear the sound of hitting the water is
t = t1 + t2, where t1 is the time it takes to hit the water and t2 is the additional time for the sound to arrive at the top of the cliff.

H - (1/2) g t1^2
t1 = sqrt (2H/g)
t2 = H/V
where V is the speed of sound in air. (Look it up).
Solve t1 + t2 = 3.7 for H

Answer 2

A rock is dropped from a sea cliff, and the sound of it striking the ocean is heard 3.1s later.