After the disappearance of Malaysia Airlines flight MH730, Inmarsat tried to use Doppler principle to calculate the whereabouts of the missing flight. The Doppler principle stems from such a physical phenomenon (Doppler effect): as the high speed of the aircraft approaches (or away from) the satellite that receives the microwave signal, the microwave frequency detected by the satellite will become higher and higher (or lower and lower).
Which of the following phenomena reflects the same Doppler effect?
When people standing near the tracks heard the whistling train coming from afar to the highway, the tone of the whistle gradually became sharp