Answer to Question #87763 in Mechanics | Relativity for Miracle

Question

A man heard the echo of his voice by a cliff 3secs later. What is the velocity of sound in air if the cliff is 510m away.

Answer 1

We can find the velocity of sound in air from the formula:

$$v_{sound} = \dfrac{Total Distance}{Time} = \dfrac{2s}{t},$$

here, $s$ is the distance traveled by the sound to the cliff (since the sound reflects back from the cliff to the man, the total distance traveled by the sound is doubled), $t$ is time.

Then, we get:

$$v_{sound} = \dfrac{2s}{t} = \dfrac{2 \cdot 510 m}{3 s} = 340 \dfrac{m}{s}.$$

Answer:

$v_{sound} = 340 \dfrac{m}{s}.$