A stone is dropped into a deep well and is heard to hit the water 2 s after being dropped. Determine the depth of the well. Assume no time delay in stone hitting the water and sound being heard. Take g= 10 ms−2.
20 m
Given, Initial velocity u = 0, g=10 ms−2, time t = 2 s
Using second equation of motion, s=ut+12gt2
s=0+12×10×2×2
Hence, depth of well = 20 m.