Question

you are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind at constant speed and you perceive the frequency as 1310 Hz. you are relieved that he is in pursuit of a different driver when he continues past you, but now you perceive the frequency as 1240 hz. what is the frequency of the siren in the police car? the speed of sound in air is 343 m/s

Answer 1

The frequency of the police car can be written as, 1310 343 v-351240) .2) 343 From the above two equations, the velocity of the car is, 343 V-35 343 1.0565 5| 1-1-35 343 1.056 343-j t 343)-10308-10 1.0565-1.0565 V-35 0.0565 343 +1.0s65 -35 343 v-35 9.417 v -44.42 m/s The frequency of the siren in the police car is, 150)-30 343 44.42-35 343 -1310 1.028) 1310 1310 0 1.028 1274.32 Hz