A car horn produces sound of frequency

PHYSICS · Subjective · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics

Problem

500\,\text{Hz}

. The car moves straight towards a high, vertical cliff at a speed of

20\,\text{m\,s}^{-1}

. The driver hears the direct sound from the horn and also the sound reflected from the cliff. If the speed of sound in air is

340\,\text{m\,s}^{-1}

, calculate the beat frequency heard by the driver.