Physics question? A factory whistle emits sound of frequency 720 Hz. When the

wind velocity is 12.1 m/s from? A factory whistle emits sound of frequency 720 Hz.
a) When the wind velocity is 12.1 m/s from the north, what frequency will observers hear who are located, at rest, due north of the whistle? Assume Temperature= 20 C
b) What frequency will observers hear who are located, at rest, due south of the whistle?
c) What frequency will observers hear who are located, at rest, due east of the whistle?
d) What frequency is heard by a cyclist heading north, toward the whistle at 11.5 m/s?
e) What frequency is heard by a cyclist heading west, toward the whistle at 11.5 m/s?