Question

A CAR IS TRAVELING AWAY FROM YOU AT 70.0 MI/H. THE CAR HORN PRODUCES A SOUND AT A FREQUENCY OF 5000HZ. WHAT FREQUENCY DO YOU HEAR?

Answer 1

f =f(o)•(1-v/V) =5000•(1- 31.3/331.3)= =4528 Hz
v =70 mph = 31.3 m/s
V =331,3 m/s (speed of sound)

Answer 2

f =f(o)•(1+v/V) =5000•(1+ 31.3/331.3)= =5472 Hz
v =70 mph = 31.3 m/s
V =331,3 m/s (speed of sound)

Answer 3

I believe you understand that the first solution is for the motion away from you, and the second solution is for the motion towards you.