I am haveing so much trouble just getting these physics problems started?

Question

A soccer player kicks a rock horizontally off a 38.0 m high cliff into a pool of water. If the player hears the sound of the splash 3.4 s later, what was the initial speed given to the rock? Assume the speed of sound in air to be 343 m/s.

Answer 1

I think I'm gonna make you more confused.

Consider; The intial speed given to the rock in the x axis is zero.

Answer 2

The rock hits the water then makes a sound. You know it was kicked horizontally so it travels

x = v0*t

Now in the same time t, it falls a distance h = 38 m so

38 = 1/2 g t^2 so you can solve for t ---> t = sqrt(2*38/g) = 2.78 seconds

He hears the sound at t = 3.4 seconds so the sound has dt 3.4 - 2.78 = 0.615 seconds

the distance x is then x= vs*dt = 343 * 0.615 = 211 m

Then v0 = 211/2.78 = 75.77 m/s