A man shoutsloudly close to a high wall, he hears an echo. If the man is 40 mfrom the wall, how long after he shouts, will the echo is heard, (speed of sound is `330 m//s`)

Explanation

The distance travelled by the sound wave
`= 2 xx` distance from man to wall.
`= 2 xx 40 `
`= 80 m.`
Time taken to travel the distance ` = ( "distance ")/("speed")`
`=( 80 m)/( 330 m//s)`
` = 0.24 s`
` therefore ` the man will hear the echo `0.24` s after he shouts .