As a football player runs towards the band sitting behind the end zone,a horn player plays a note with frequency f.The frequency,$f'$,that the football player hears is
A)twice as high as f.
B)slightly higher than f.
C)the same as f.
D)slightly lower than f.
E)half of f.

Question

Quizplus · Accepted Answer

This phenomenon is explained by the Doppler effect, which states that the frequency of a wave, as perceived by an observer, increases if the source of the wave and the observer are moving closer to each other. Since the football player is running towards the horn player, the frequency of the note heard by the player will be slightly higher than the frequency of the note as it is played.

As a Football Player Runs Towards the Band Sitting Behind f′f'f′

As a Football Player Runs Towards the Band Sitting Behind $f'$