Question

A man standing 48 m away from a wall fires a gun. Calculate the time after which an echo is heard. (The speed of sound in air is 320 ms^-1).

Answer 1

Man's distance from the wall = 48 m

∴ 2d = for going and coming = 2 × 48 = 96 m

Speed of sound in air V = 320 ms^-1

∴ Time after which echo is heard t = `(2d)/V`

t = `96/320`

= `3/10`

= 0.3 s