A car moving at 25m/s approaches a stationary whistle that emits a 350Hz sound. The speed of sound in the air is 343m/s
A) what is the frequency of sound heard by the driver of the car?
B) what is the frequency of sound heard by the driver of the car after passing the whistle and moving away from it?
C) what is the frequency of sound heard by the driver of the car if the whistle is also moving toward the car at 12m/s?
D) what is the frequency of sound heard by the driver of the car if the whistle is now moving in the same direction as the car with a speed of 12m/s?