The Doppler Effect Video Lessons

Concept

# Problem: A student knows that an ambulance siren has a frequency of fs = 399 Hz. He measures, when the ambulance is approaching him.  The frequency fo = 414 Hz. Assume the speed of sound is v = 343 m/s in this problem.(a) Input an expression for the ambulance's speed, vs, in terms of the frequencies and the speed of sound v (b) What is this speed, in meters per second?

###### FREE Expert Solution

Change in frequency when the source is approaching:

(a)

###### Problem Details

A student knows that an ambulance siren has a frequency of fs = 399 Hz. He measures, when the ambulance is approaching him.  The frequency fo = 414 Hz. Assume the speed of sound is v = 343 m/s in this problem.

(a) Input an expression for the ambulance's speed, vs, in terms of the frequencies and the speed of sound v

(b) What is this speed, in meters per second?