# Two train whistles, A and B , each have a frequency of 396 Hz . A…

Two train whistles, A and B , each have a

frequency of 396 Hz . A is stationary and B is

moving toward the right (away from A ) at a speed of 35.0

m/s . A listener is between the two whistles and is moving toward

the right with a speed of 15.0 m/s . (See (Figure 1) .)

Part A

What is the frequency from A as heard by the

listener?

Express your answer in hertz

Part B

What is the frequency from B as heard by the

listener?

Express your answer in hertz

Part C

What is the beat frequency detected by the listener?

Express your answer in hertz

UL 15.0 m/s vB 35.0 m/s