Doppler Effect

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Question 17: The relative speed between the whistle and the listener is highest at point C. By today's discussion of the Doppler effect, this must also be the location of the highest frequency.

51.
a) Vobs = 370 m/s, Vsource = 340 m/s, fobs = 1959 Hz
b) Vobs = 310 m/s, Vsource = 340 m/s, fobs = 1631 Hz

52. The frequency of the wave as heard by the moving object is 46323 Hz. This frequency now acts as the source, and the bat is the observer. The new frequency heard by the bat is 43150 Hz.

78. You should be able to set up two equations with Fsource and v(the speed of the train) as the unknowns. Let Vs stand for the speed of sound.
First equation: Vs/(Vs - v) = 522/Fsource
Second equation: Vs/(Vs + v) = 486/Fsource.

Dividing the equations, Fsource drops out, and you can solve numerically to get v = 12.14 m/s.

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