This video shows the Doppler Effect when the source of a sound moves at 100 m/s toward a stationary observer. Later, the same source is seen moving away from the observer. Since the source of the sound is in motion relative to the observer, the observer will hear the sound with a different perceived frequency labeled f'. . The speed of sound is 343 m/s the frequency of sound is 343 Hz the wavelength λ of the sound wave is 343 m/s / 343 Hz = 1 m We will find the perceived frequency f' heard by th