Question

a pendulum has a frequency of 5 vibrations per second and observer starts the pendulum and fire the gun simultaneously he hears an echo from the Cliff after 8 vibrations of the pendulum if the velocity of sound in air is 340 metre per second find the distance between the Cliff and the observer.

Answer 1

5 vibrations - 1 second
1 vibration- 1/5 second
8 vibrations- 1*8/5 second

Therefore time is = 8/5=1.6 seconds

Speed of sound - 340 m/s (Given)

Therefore - Distance= Vt/2

So
V=340 m/s
t=1.6 seconds
d=?

Distance=Vt/2
=(340*1.6)/2
=272 m Answer


Plzz correct ur question. speed of sound will be 340 m/s and not 340 m

Answer 2

frequency (f)=5

time period (t)=1/f

=1/5

=0.2 s

Time for 8 vibrations

=8×0.2 = 1.6 s

Distance btw observer and cliff be d.

$d = \frac{v \times t}{2}$

$= 340 \times 1.6$

$= 272m$

hope it will help you.....