A model airplane traveling at 5 m/s approaches you. The frequency of the hum produced by the motor is 652 Hz. Assume the speed of sound to be 342 m/s. What is the observed frequency of the hum?

643 Hz

647 Hz

657 Hz

662 Hz

Verified Answer :

To calculate the frequency change of a moving source, the formula used is:

f = cfo/(c+Vs)

where:
f = frequency observed
c = speed of sound
Vs = speed of source (positive if it's moving away from observer and negative if it is moving towards the observer)
fo = emitted frequency of the source

f = 342
652/(342-5)
f = 661.67 Hz or 662 Hz --> FINAL ANSWER

Answer:

662

Explanation: