When an automobile moves towards a listener, does the sound of its horn seem relatively low pitched, high pitched or normal?

1 Answer
Mar 9, 2018

Higher than normal pitch.


The peak of the sound wave that arrives at #t = t_1# did not have to travel as far as the previous peak did because the car came closer. That means that the time between the 2 peaks was less than if the car was standing still. Frequency, #f#, is

#f = "number of peaks"/(time)#

Therefore the frequency you heard was higher than if the car was standing still. Higher frequency means higher pitch.

I hope this helps,