What Frequency Does Sub A Detect for the Reflected Sonar Wave?

[sailordragonball]

Two submarines are underwater and approaching each other head-on. Sub A has a speed of 12 m/s and sub B has a speed of 17 m/s. Sub A sends out a 1520 Hz sonar wave that travels at a speed of 1522 m/s.

... I already solved for this question ...

... What is the frequency of the sound detected by sub B (to the nearest Hz)? ...

... I used the Doppler equation and I got 1549 Hz as an answer, which is correct.

... My next question is ...

... Part of the sonar wave is reflected from B and returns to A. What frequency does A detect for this reflected wave (to the nearest Hz)?

... do I use the Doppler equation again ... or is there a reflection equation or concept that I missed out on?

 

[OlderDan]

Two submarines are underwater and approaching each other head-on. Sub A has a speed of 12 m/s and sub B has a speed of 17 m/s. Sub A sends out a 1520 Hz sonar wave that travels at a speed of 1522 m/s.

... I already solved for this question ...

... What is the frequency of the sound detected by sub B (to the nearest Hz)? ...

... I used the Doppler equation and I got 1549 Hz as an answer, which is correct.

... My next question is ...

... Part of the sonar wave is reflected from B and returns to A. What frequency does A detect for this reflected wave (to the nearest Hz)?

... do I use the Doppler equation again ... or is there a reflection equation or concept that I missed out on?

Yes, you use it again, but perhaps not exactly the same way. Whatever the frequency of the reflected sound sub A is moving when it receives it.