Answer:
(a): The frequency received by the observers is f'= 138,062.28 Hz.
(b): When the plane flies directly away from them, they receive a frequency of f'= 1772.46 Hz.
Step-by-step explanation:
Vf= 333.33 m/s
Vo= 0 m/s
V= 342 m/s
f= 3500 Hz
(a) f' = f * ( V / (V - Vf) )
f'= 138062.28 Hz
(b) f'= f* ( V / (V - (- Vf) )
f'= 1772.46 Hz