The police car with its 300-Hz siren is moving away from the warehouse at a speed of 16.0 m/s . . . What frequency does the driv

Question

zimovet [89]

3 years ago

13

The police car with its 300-Hz siren is moving away from the warehouse at a speed of 16.0 m/s . . . What frequency does the driv

er of the police car hear reflected from the warehouse?. . Use 344m/s for the speed of sound in air.

Physics

2 answers:

bazaltina [42] · Answer 1 · 2022-09-16T17:23:13+03:00

bazaltina [42]3 years ago

8 0

Frequency heard by listener: fl = ?
frequency of source: fs = 300 Hz
velocity of listener: vl = 16 m/s
velocity of source: vs = 0
velocity of sound in air: c = 344 m/s

fl = fs [(c – vl)/c] = 300[(344-16)/344]
 =286.04 Hz

Morgarella [4.7K] · Answer 2 · 2022-09-16T18:29:18+03:00

<h3>Answer;</h3>

= 286.05 Hz

<h3>Explanation;</h3>

We can use or employ the Doppler equation:

fl = fs[(c±vl)/(c-/+vs) 

where,

frequency heard by listener: fl = ?
frequency of source: fs = 300 Hz
velocity of listener: vl = 16 m/s
velocity of source: vs = 0
velocity of sound in air: c = 344 m/s

The source will be the origin of the reflected signal (i.e.the

warehouse). So that, velocity of source: vs = 0

The listener is the policeman moving away from the source 

with velocity: vl = 16 m/s

Therefore, the Doppler equation. becomes: 

fl = fs [(c – vl)/c] 

= 300[(344-16)/344] 

= 286.04 Hz 

where, fl is the frequency of the reflected sound heard by

the police officer.