A car is traveling at a speed of 36 km/h when an ambulance with its siren on approaches it from behind at a speed of 90 km/h. The siren emits a tone with a frequency of 400 Hz. What frequency does the car driver hear if:
there is no wind?
the wind blows in the direction of travel of both vehicles at a speed of 20 m/s?
both vehicles are stationary and only the wind is blowing?
The speed of sound in the air is 340 m/s.
