Question

A man stands at a distance of 68 m from a cliff and fires a gun. After what time interval will he hear the echo, if the speed of sound in air is 340ms^-1? 

Answer 1

Given:

d = 68m, v = 340ms-1.

∴ Time taken = (total distance)/speed = 68/340 = 1/5 = 0.2s(second)

so echo is heard after 2t i.e.

0.2 x 2 = 0.4 sec.