Posted by **Jeff J.** on Friday, September 16, 2011 at 2:25pm.

One can get a good idea of how deep a well is, for example, by dropping a rock and listening to how long it take to hear the rock as it hits the bottom. Suppose a rock was dropped into a well that was 410 meters deep and after the rock hits the bottom, a sound wave travels at a constant speed of 303 m/s upwards until it reaches your ears and you actually hear the rock. How long will it take, in seconds, to hear the rock from the moment it is dropped?

- Physics -
**bobpursley**, Friday, September 16, 2011 at 4:36pm
Figure the time to fall:

410=1/2 g t^2 solve for time

then figure time for sound to come up:

410=vs*time

add the times.

As a practical matter, one can't hear the rock very well, it hits the sides going down, slows, bounces, so the entire process is not very accurate. I dispute that it is "good idea".

## Answer This Question

## Related Questions

- physics - A rock is tossed straight up with a speed of 29m/s. When it returns, ...
- physics - A rock is tossed straight up with a velocity of 34.0 m/s. When it ...
- phisics - a rock is tossed straight up with a speed of 30m/s. when it returns it...
- physics - Question 1) A rock is dropped from the top of a 100 meter tall cliff...
- physics - A rock is tossed straight up with a velocity of 37.1 m/s. When it ...
- Physics - A mine shaft is known to be 57.8 m deep. If you would drop a rock ...
- Physics - A mine shaft is known to be 57.8 m deep. If you would drop a rock down...
- physics - a rock is dropped from a height of 15m above the ground. when it hits ...
- physics - a rock is dropped from a height of 15m above the ground. when it hits ...
- Physics - A rock is thrown horizontally off of a cliff. It starts with a ...

More Related Questions