Doppler shift of an approaching source with interference problem

[Solidearth]

Homework Statement

P15. The police car with its 300 Hz siren is moving toward a warehouse at 30 m/s, intending to crash through the door. What frequency does the driver of the police car hear reflected from the warehouse? (5 marks)

Homework Equations

doppler shift for an approaching source. (f+) = fo / [1-vs/v]

The Attempt at a Solution

the doppler shift of the siren at the door is (300Hz)/ (1- [(30m/s)/(343m/s)]) =328.75Hz

now assume that the warehouse/ warehouse door reflects 100% of the incident waves.

I really have no idea where to go from here.

 

[rl.bhat]

For reflected waves, treat source at rest and the observer is moving towards the source with the velocity equal to the velocity of the police car.

 

[Simon Bridge]

The warehouse reflects each wave that hits it, and becomes a source.
The car is driving through the reflected waves.

 

[Solidearth]

hey guys thanks for the reply I tried it and it worked.
cheers

 

[asteriatic]

I would first clarify the problem by asking for more information. Is there any interference present in the scenario, and if so, what type of interference is it? Is the warehouse door made of a material that could potentially absorb or reflect the sound waves differently? Are there any other factors that could affect the frequency of the reflected sound wave?

Once these questions are answered, I would then use the appropriate equations and principles to calculate the frequency of the reflected sound wave. This may involve taking into account the change in wavelength due to interference, as well as any changes in the speed of sound due to the material properties of the warehouse door.

I would also consider the practical implications of this scenario, such as the potential for the reflected sound wave to interfere with the police car's siren and cause confusion or difficulty in navigating the vehicle. This could lead to further investigation and experimentation to find a solution to this problem.

Overall, as a scientist, my response would be to gather more information, consider all relevant factors, and use scientific principles and methods to find a solution to the problem.