At that speed of the second plane, there will be a weak oblique shock wave in front of it. Sound waves that pass through the shock wave will enter a denser slower medium, with a different sound speed. This question is harder than it looks to do correctly.
Neglecting shock wave issues, there will be an upshift in frequency of about (380-280)/340 x 17500 Hz
That will put the received frequency at about 22,650 Hz.
Humans cannot hear that frequency
The 17500 Hz whine of the turbines in the jet engines of an aircraft moving with speed 280 m/s is heard at what frequency by the pilot of a second craft trying to overtake the first at a speed of 380 m/s?
1 answer