Calculate the Depth of a Well: u, a and Time Given

[milto]

Homework Statement

How deep is the well remember its takes him 3.8 seconds to hear the stone hit the bottom not 3.8 to see it hit the bottom.
u=0ms^-1
a=10ms^-2

Homework Equations

Not 100% sure what equations to use because my teacher goes to quickly

The Attempt at a Solution

Would you be able to show me the equations to use to solve it.
Thanks Nick.

 

[Carid]

Try these

Depth = InitialSpeed*DropTime + 0.5*Acceleration*DropTime²

SpeedOfSound = Depth/EchoTime

TotalTime = DropTime + EchoTime

 

[milto]

Thanks mate, I got 35.28m for the depth of the well, is that correct??

 

[Carid]

Dunno mate! I didn't get that far.