Question

A boy standing in front of a high rise building receives his echo in 8 seconds. Find the distance between him and the building when the speed of the sound in air is 340 m/s.​

Answer 1

Answer:

1360 m

Explanation:

t=8sec, V=340m/s, d=?

$formula => \: \: \: \: \: v = 2d \div t$

340 = 2d ÷ 8

d= 340 × 8 ÷ 2 = 1360m Ans

Hope it helped:)

Answer 2

Answer:

The distance between him and the building is 2.720km

Explanation:

Let d be the distance of cliff from the boy . Therefore total distance covered by sound to go to cliff and come back to boy after reflection from cliff

$= 2d$

given

$v = 340ms, \: t = 8s$

we have,

$distance = speed \times time, \\ 2d = v \times t = 340 \times 8 \\ or \\ d = 340 \times \frac{3}{2} \\ = 2720m = 2.720km$