Question

A man makes a loud holler. He hears an echo 2 seconds later. If the air temperature is 25 0C, how far is he from the source of the echo?

Answer 1

ANSWER

If the man plays a sound, then the sound waves travel towards the cliff, get reflected, return and then fall on his ear. This is how he hears an echo.

Thus the sound travels twice the distance between him and the cliff.

$∴distance(s)= </p><p>2</p><p>speed×time$

$∴s= </p><p>2</p><p>330×2</p><p> </p><p> =330 metres$

Thus 330 metres is the distance between him and the 1st cliff.

Since he hears the 2nd echo after the same time interval, the 2nd cliff is also at a distance of 330 metres from him.

Hence the distance between the 2 cliffs will be 330+330=660m.