Problem
A physics student walks down a long hall carrying a vibrating 512-Hz tuning fork. The end of the hall is closed so that sound reflects from it. The student hears a sound of 516 Hz from the wall. How fast is the student walking? Assume speed of sound is 340 m/s
The student serves as a source moving toward the wall, and a moving receiver for the echo.
u/v = (516-512)/(516+512)= 4/1028
speed of student = 4(340)/1028 m/s = 1.32 m/s.