Question

child has an echo from a cliff 4 seconds after the sound from a powerful crackers is produced how far away is the Cliff from the child

Answer 1

child ear 4 sec
there for taken by sounf cliff = 4upon2 = 2 sec

speed of sound in air v= 340 meter pr sec
distance of cliif for the child =vt

340×2 =680 m answer