# Free fall and distance

1. Jul 25, 2017

### Sunsethorizon

1. The problem statement, all variables and given/known data
A stone falls from top of a well, 10 seconds later sound of water splash reaches the top of the well. How deep is the well?

g=9.82m/s2, vsound=340m/s , t=10s

2. Relevant equations

s=vt , v=a0+at , s=v0t+1/2at2

3. The attempt at a solution
I'm stuck. I know the distance of the soundwaves traveling from the bottom to the top of the well is given by s=vt. And the distance the rock travels is given by s=v0t+1/2at2.

Do i try figure out for how long the rock travels before hitting the bottom?, Or are equations supposed to be merged? Please point me in the right direction :)

2. Jul 25, 2017

### .Scott

In this case, the initial velocity is 0, so the distance is s=1/2at^2.
For the sound return, s=340m t.
So you need your two s's to be equal and your two t's to add to 10 seconds.

3. Jul 25, 2017

### scottdave

Use t in one of the equation for motion, and (10 - t) in the one for sound. Set the distances equal to each other. Once you have t, you can find the distance in the usual fashion.

4. Jul 26, 2017

### Sunsethorizon

Thank you! Excellent help gentlemen, i fully understand now.