Multiple Choice
A policeman in a stationary car measures the speed of approaching cars by means of an ultrasonic device that emits a sound with a frequency of 41.2 kHz.A car is approaching him at a speed of 33.0 m/s.The wave is reflected by the car and interferes with the emitted sound producing beats.What is the frequency of the beats? The speed of sound in air is 
.
A) 9.2 kHz
B) 4.1 kHz
C) 4.6 kHz
D) 1.2 kHz
E) 8.2 kHz
Correct Answer:
Verified
Correct Answer:
Verified
Q55: The lowest-pitch tone to resonate in a
Q56: An enclosed chamber with sound absorbing walls
Q57: A certain crying baby emits sound with
Q58: Radio station KBOB broadcasts at a frequency
Q59: A string,0.28 m long and vibrating in
Q61: A certain source of sound waves radiates
Q62: A 0.25-m string,vibrating in its sixth harmonic,excites
Q63: A woman is riding a bicycle at
Q64: In a resonating pipe that is open
Q65: A 1.30-m long gas column that is