Question

A boy standing in front of a high rock claps once and hears the echo of his clap after 2.5 seconds. If velocity of sound is 340m/s , find the distance of the boy from the rock​

Answer 1

Explanation:

Let d1 and d2 be the distances of cliffs from the boy .

for first echo , which is heard after 2s ,

total distance travelled by sound =2d1 ,

given v=330m/s ,

we have , distance=speed×time ,

               2d1=330×2 ,

or            d1=660/2=330m ,

for second echo , which is heard after 2.5s ,

total distance travelled by sound =2d2 ,

given v=330m/s ,

we have , distance=speed×time ,

               2d2=330×2.5 ,

or            d2=825/2=412.5m ,

therefore , distance between cliffs , d=d1+d2=330+412.5=742.5m