A rock is dropped from a seacliff and the sound of it striking the ocean is heard 3.4 seconds later. If the speed of sound is 340 m/s, how high is the cliff? I think the answer is 46 m but i don't get how it is that answer?

Question

anonymous · Answer

$$h=ut + at^2/2$$

Since the Stone is Dropped u = 0

$$h = at^2/2$$

here a=g

anonymous · Answer

$$t _{1} +  t _{2} =3.4$$
$$h= 340 t _{2} $$
$$h = \frac{ g(3.4-t _{2})^2 }{ 2 }$$
$$ h = \frac{ g(3.4-\frac{ h }{ 340 })^2 }{ 2 }$$