Question

A source emits sound with a frequency of 860 Hz. It is moving at 20.0 m/s toward a stationary reflecting wall. If the speed of sound is 343 m/s, what frequency does an observer riding with the source hear

Answer 1

Step-by-step explanation:

f = 860 Hz

velocity of source, vs = 20 m/s

velocity of sound, v = 343 m/s

use the formula of doppler's effect

the frequency reflected from the wall is

`f' = (v)/(v+ v_(s))* f`

`f' = (343)/(343+20)* 860`

f' = 812.62 Hz

Frequency heard by the observer

`f'' = (343)/(343-20)* 812.62`

f'' = 862.93 Hz