A police radar gun used to measure the speed of cars emits an electromagnetic wave (a radio wave) with a frequency of $24\text{GHz}.$ In an area where the speed limit is $30\text{ m/s},$ what should be the shift in the frequency of the wave after reflecting off traffic that is exactly following the speed limit, driving toward the police officer?

(II) A police car sounding a siren with a frequency of 1580 Hz is traveling at 120.0 km/h .

(c) The police car passes a car traveling in the same direction at 80.0 km/h. What two frequencies are heard in this car?

(III) A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency will observers hear who are located, at rest,

(b) due south, of the whistle?

(III) A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency will observers hear who are located, at rest,

(c) due east, of the whistle? and

A police siren emits a sound somewhere around 700 Hz. If you are waiting at a red light, and a police car approaches you from behind and passes you, moving at a constant 30 m/s, what is the frequency you hear from the siren as it approaches you from behind? What about once it's passed you? Assume the air temperature to be 20°C.