Question

A man standing 50m in front of a wall and claps his hands. What is the time between the clap and the echo, given that the speed of sound in air is 330m/s

Answer 1

Each clap must occur at the instant the echo of the last one returns. Claps occur every (3 seconds)/5 = 0.6 second. The sound travels to the wall and back, or 100+100 m = 200 m in this time (= 0.6 sec). Hence velocity (distance per unit of time) is (200 m)/(0.6 sec) = 333.33 m/sec.