So I watched 'Journey to the center of the earth' today, and I was reminded of a common physics question. Like if you were to let a stone fall; the seconds between when released and when the sound of the stone hitting the ground is heard indicates the distance to the ground.

Method:

For e.g.

It falls----------->It hits------------------->Its heard
0-------------->X seconds-------------->23seconds later

Sound travels at 343m/s

d = 0.5gt²

Assuming X is 16:

= 9.8 * 16² * 0.5
= 1254.4m

Time it takes to be heard, 1254.4/343 i.e. the time between x and the time it was heard.
=3.65seconds

3.65 + 16seconds = 19.65 seconds. Thus X must be >16

The table below indicates the second-distance (for up to 20seconds) with relative accuracy.



The Calculator below works in excel 2007. Just type in the seconds in the colored box and press enter. http://www.wikiupload.com/comment.php?id=46047

p.s. you need to activate continous via going to excel options>formulas> and tick allow iterations