Suppose a man stands at a distance from a cliff and claps his hands. He receives an echo from the cliff after 4 second. Calculate the distance between the man and the cliff. Assume the speed of sound to be 343 m s-1.
The time taken by the sound to come back as echo is 2t = 4 ⇒ t = 2 s
∴The distance is d = vt =(343 m s-1)(2 s) = 686 m.