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 o

Question

Vlad [161]

3 years ago

15

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 o

f sound to be 342 m/s. What is the observed frequency of the hum?
643 Hz
647 Hz
657 Hz
662 Hz

Physics

1 answer:

iogann1982 [59] · Answer 1 · 2022-05-21T16:28:55+03:00

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

f = c*fo/(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