A 520 Hz whistle is moved toward a listener at a speed of 20 m/s. At the same time, the listener moves at a speed of 45 m/s in a direction away from the whistle. What is the apparent frequency heard by the listener? (The speed of sound is 340 m/s)

The Doppler effect is a change in the observed frequency of a wave (such as a sound wave or light wave) when the source of the wave and observer are in motion relative to each other. The Doppler effect explains why an observer hears a change in pitch of an ambulance siren as the ambulance passes by the observer. The frequency F(v) of a sound relative to So an observer is given by F(v) = fal , where fa is the actual frequency of the sound at the source, so is the speed of sound in air (772.4 mph), and v is the speed at which the source of sound is moving toward the observer. Use this relationship for Exercise. Suppose that an ambulance moves toward an observer. a. Write F as a function of v if the actual frequency of sound emitted by the ambulance is 560 Hz. b. Use a graphing utility to graph the function from part (a) on the window [0, 1000, 100] by [0, 5000, 1000]. C. As the speed of the ambulance increases, what is the effect of the frequency of sound?

Ultrasound reflected from an oncoming bloodstream that is moving at 33.0 cm/s is mixed with the original frequency of 1.50 MHz to produce beats. What is the beat frequency (in Hz)?

A sound source with a frequency of 725 Hz moves away from a stationary observer at a rate of 15m/s. What frequency does the observer hear?