Question

An observer stands at a distance of 660m from the cliff and fires the gun.After what time gap will he hear the echo if the sound travels at a speed of 330m/s

Answer 1

d=660m
v=330m/s
v=2d/t
=2×660/330
=4 sec

Answer 2

$\Longrightarrow{\boxed{\bold{\huge{Answer: 4\:s }}}}$

$\textbf{\underline{Step-by-step explanation :- }}$

$\bold{\large{Speed = \frac{Distance}{Time}}}$

Speed of sound in air = 330 m/s

Distance = 660 m

But in echo sound travels same path twice, that's why

By substituting values we get,

$\bold{\huge{ s = \frac{2d}{t}}}$

330 m/s = 2 × 660 m / t

t = ( 660 m / 330 m/s ) × 2

$\boxed{\bold{\underline{\large{t\:=\:4\:s}}}}$

Hence 4 s will be taken by sound to reach the observer.