【Daily Question】Theoretical Foundation 2020.06.01
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Multiple-choice question: A police car is chasing a bus that is moving at 15 m/s through still air, with the police car itself moving at 25 m/s. If the frequency of the police car’s siren is 800 Hz and the speed of sound in air is u = 330 m/s, then what is the frequency of the siren’s sound waves as heard by the people on the bus? ( ) (A) 710 Hz (B) 777 Hz (C) 905 Hz (D) 826 Hz. Answer: D. Hint: Those who can explain the solution process will receive an additional reward; the answer can be found in the response!
This post was last edited by Song Yonggang15532757608 on 2020-6-1 10:58. D
The last edit to this post was made by h20090630 on 2020-6-1 at 11:43; it concerns the frequency of the police siren waves heard by passengers in a C-class bus