A train passes a stationary observer. Which of
the following best describes how the amplitude
and the apparent frequency of the sound waves
heard by the observer change as the train moves
away?

A)Both the amplitude and the apparent
frequency increase
B)Both the amplitude and the apparent
frequency decrease
C)The amplitude of the sound waves
increases, and the apparent frequency
decreases.
D)The amplitude of the sound waves
decreases, and the apparent frequency
increases