How to Calculate Distance Using the Doppler Effect

[leinad0213]

Homework Statement

A physics student drops a vibrating 421 Hz tuning fork down the elevator shaft of a tall building. The temperature in the shaft is 20 °C. When the student hears a frequency of 392 Hz, how far has the tuning fork fallen?

f_S = 421 Hz
f_L = 392 Hz
V_SOUND = 343 m/s

Homework Equations

Doppler Equation: f_L = f_s(V_SOUND + V_listener)/(V_SOUND + V_Source)

The Attempt at a Solution

I solved for the velocity of the source and got 25.38 m/s but I don't really get how I would apply it to this problem. If only I had time.

 

[HallsofIvy]

How does the velocity of a dropped object incresase?