Question

If a boy heard third echo of his sound after 4 second, the distance of cliff from boy is (velocity of sound in air is 330 m/s)

Answer 1

ANSWER

Let d

1

and d

2

be the distances of cliffs from the boy .

for first echo , which is heard after 2s ,

total distance travelled by sound =2d

1

,

given v=330m/s ,

we have , distance=speed×time ,

2d

1

=330×2 ,

or d

1

=660/2=330m ,

for second echo , which is heard after 2.5s ,

total distance travelled by sound =2d

2

,

given v=330m/s ,

we have , distance=speed×time ,

2d

2

=330×2.5 ,

or d

2

=825/2=412.5m ,

therefore , distance between cliffs , d=d

1

+d

2

=330+412.5=742.5m

I hope you are understand my solution

Answer 2

Answer:

Let d

1

and d

2

be the distances of cliffs from the boy .

for first echo , which is heard after 2s ,

total distance travelled by sound =2d

1

,

given v=330m/s ,

we have , distance=speed×time ,

2d

1

=330×2 ,

or d

1

=660/2=330m ,

for second echo , which is heard after 2.5s ,

total distance travelled by sound =2d

2

,

given v=330m/s ,

we have , distance=speed×time ,

2d

2

=330×2.5 ,

or d

2

=825/2=412.5m ,

therefore , distance between cliffs , d=d

1

+d

2

=330+412.5=742.5m

Explanation:

hope it helps you ❣️