Question

a person standing between two vertical cliffs and 480m from the nearest cliff shouts . He hears the first echo after 3 s and the second echo 2s later

Answer 1

Explanation:

i) Total distance travelled by the sound in goingand coming back = twice of 480m

Speed of sound =

Total distance travelled /time taken

= 960/3= 320m/s

Time taken to reach second echo= 3+2 =5sec

Therefore, v=2d/t

=> d=vt /2

ii)Distance of other cliff from the person =

320[5]/2 = 800m

Hope it helps ....

Answer 2

The first eco is heard from the nearest Cliff.

Let d1 be the distance of the nearest cliff.

The distance travelled by sound is going and coming back from the nearest Cliff is

S1=2d1=480×2=960m

Time intervel t1 = 3s

Therefore, Speed of sound is

$v = \frac{total \: distance \: travelled}{tim \: taken}$

$\frac{960}{3} = 320ms {}^{ - 1}$

The second echo is heard from the farther cliff. If d2 is the distance from the person, then distance travelled by sound

S2=2d2 and time taken t2=3+2=5s

$v = \frac{s2}{t2} \\ 320 = \frac{s2}{5} \\ s2 = \: 320 \times 5 = 1600 \: mm$