Question

A fly buzzes past you at 6 m/s. the frequency of the buzz made by its wings is 162 hz. assume the speed of sound to be 334 m/s. what is the observed frequency of the hum as the bumblebee approaches you?

O 328 Hz
O 168 Hz
O 165 Hz
O 156 Hz

Answer 1

Using the Doppler Effect equation, the observed frequency of the hum as the fly approaches is calculated to be approximately 168 Hz. Option B is correct.

Step-by-step explanation:

The student's question involves the Doppler Effect, which describes the change in frequency of a wave in relation to an observer who is moving relative to the wave source. To calculate the observed frequency as the fly approaches, we use the Doppler Effect equation for sound moving towards an observer as follows:

f' = f(\(v + v_o\))/(v - v_s)

In this equation, f' is the observed frequency, f is the source frequency, v is the speed of sound, v_o is the observer's speed (which is 0 in this case, as the observer is stationary), and v_s is the source's speed. The source here is the fly, and it is moving towards the observer. Plugging in the values:

f' = 162 Hz * (334 m/s + 0 m/s)/(334 m/s - 6 m/s) = 162 Hz * (334 m/s)/(328 m/s) = 168 Hz (approx)

Therefore, the observed frequency of the hum as the fly approaches is approximately 168 Hz.