A fixed source of sound emitting a certain frequency appears as when the observer is…

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics

Problem

A fixed source of sound emitting a certain frequency appears as

f_a

when the observer is approaching the source with speed

v_0

and

f_r

when the observer recedes from the source with the same speed. The frequency of the source is (1)

\frac{f_r+f_a}{2}

(2)

\frac{f_r-f_a}{2}

(3)

\sqrt{f_a f_r}

(4)

\frac{2f_r f_a}{f_r+f_a}