Need help in physics 11

Question

How do I find out what the initial and final velocity is? for ex. A stone tumbles into a mineshaft and strikes bottom after falling for 4.2 secs. how deep is mineshaft. I am confused by which velocity we try to find and which velocity is 0 m/s. Is there any technique in solving word problems we could use to find out which is which (initial and final velocity)

Answer 1

The useful tool here is what might be called the "free-fall equation": d= 1/2 * a * t^2, d = distance, a - acceleration---in this case, the acceleration of gravity---32 ft/sec^2---or 9.1 m/sec^2