Question

A man shouts loudly close to a high wall. He hears an echo. If the man is at 40 m from the wall, how long after the shout will the echo be heard?

(speed of sound in air = 330 m/s)

Answer 1

Given: s = 40m, v = 330 m/s

To Find: time (t)

Formula: Time = distance \(\frac{distance}{speed}\)

Calculation:

The distance travelled by the sound wave

= 2 × distance from man to wall.

= 2 × 40 = 80 m.

From formula,

∴ Time taken to travel the distance

\(\frac{distance}{speed}=\frac{80}{30}\) = 0.24 s