当声音远离的计算假如声源是400Hz的频率,并且以30m/s的速度远离,你听到的声音频率是多少?（好像有点不通,附上原文）Supposethatthesourcehasafrequencyof400Hzandismovingawayfromyouat30m/s,whatis

Question

当声音远离的计算
假如声源是400 Hz的频率,并且以30m/s的速度远离,你听到的声音频率是多少?（好像有点不通,附上原文）
Suppose that the source has a frequency of 400 Hz and is moving away from you at 30m/s,what is the frequency of the sound that you hear?

Answer 1

假设原有波源的波长为λ,波速为c,观察者移动速度为v：
当观察者走近波源时观察到的波源频率为（c+v）/λ,如果观察者远离波源,则观察到的波源频率为（c-v）/λ.
λf=c,
观察到的波源频率为（c-v）/λ=(c-v)f/c=(340-30)*400/340=364.7Hz