You are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind and you perceive the frequency as 1,310 hz. you are relieved that he is in pursuit of a dierent speeder when he continues past you, but now you perceive the frequency as 1,240 hz. what is the frequency of the siren in the police car? the speed of sound in air is 343 m/s.
