A Car Approaches You at a Constant Speed, Sounding Its

Multiple Choice

A car approaches you at a constant speed, sounding its horn, and you hear a frequency of 76 Hz. After the car goes by, you hear a frequency of 65 Hz. What is the frequency of the sound emitted by the horn? The speed of sound in air is 343 m/s.

A) 68 Hz
B) 69 Hz
C) 70 Hz
D) 71 Hz
E) 72 Hz