13 WAVE MOTION 13.6 The Doppler effect
(^) ×
in the frame of reference of the source. We have chosen a minus sign in the
numerator of the above formula because the observer is moving away from the
source, leading to a downward Doppler shift. We have chosen a minus sign in
the denominator of the above formula because the source is moving towards the
observer, leading to a upward Doppler shift. Hence,
fJ =
1 − 33/343
500 = 514.95 Hz.
1 − 42/343