Question

A person fires a gun and starts oscillating a pendulum at the same time.He heard the echo of gunfire after 8 oscillations of the pendulum.If the frequency is 0.5 heartz then calculate the distance of the person from the reflector,where the speed of sound in air is 320m/s.​

Answer 1

Answer:

He hears the echo after 8 oscillations

Frequency of oscillations = 0.5Hz

Time period of oscillation = 1/f = 1/0.5 = 2s

So time period of 8 oscillations = 8 x 2s = 16s

The person Therefore hears the sound(echo) after 16s

In this 16s, the sound travels and hit the target and reflect back. So it travels '2d' before the person hears the echo.

Where 'd' is the distance between the person and the reflector

Distance = velocity x time

2d = 320m/s x 16s

d = 2560m

The distance between the person and the reflector is 2560m