You Are Driving Along a Highway at 35 $1340 \mathrm {~Hz}$

question 42

Multiple Choice

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 $1340 \mathrm {~Hz}$ You are relieved that he is in pursuit of a different driver when he continues past you,but now you perceive the frequency as $1300 \mathrm {~Hz} .$ What is the speed of the police car? The speed of sound in air is $343 \mathrm {~m} / \mathrm { s } .$

• A)38.4 m/s
• B)30 m/s
• C)39.2 m/s
• D)40.1 m/s
• E)41.7 m/s