Question

3. An observer standing between two cliffs fires a gun. He hears the first echo after 1 second and the
next after 3 seconds. Find
(a) his distance from the nearer cliff.
(b) his distance between the two cliffs.
(Velocity of sound = 330 ms)

Answer 1

(a) his distance from the nearest cliff = 165 m

(b) the distance between the two cliffs = 660 m

Let the distance between the two cliff = d

Let the distance of the person from nearest cliff = x

Then the distance of the person from the other cliff = d-x

The first echo which is heard after reflections from the nearest cliff -

2x = 330 × 1

=> x = 165 m

The distance of the person from the nearest cliff = 165 m

The second echo is heard after reflection from the other cliff-

2(d-x) = 330 × 3

=> d - 165 = 495

=> d = 660 m

The distance between the two cliffs = 660 m

Answer 2

Answer:

a)165m, b) 660

Explanation:

velocity =

time =3 second and 1 second

Formula - h=VT/2

b) h= 330x3+1 /2

h= 330x4 /2

h= 1320/2

h= 660 Ans