18. Waves & Sound

A police car sounding a siren with a frequency of 1580 Hz is traveling at 120.0 km/h. What siren frequencies are heard in a car traveling at 90.0 km/h in the opposite direction before and after passing the police car?

A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency will observers hear who are located, at rest, due west, of the whistle?

A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency is heard by a cyclist heading north, toward the whistle at 12.0 m/s? Assume T = 20 °C .

(III) A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency will observers hear who are located, at rest, due north, of the whistle?

A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency is heard by a cyclist heading west, toward the whistle at 12.0 m/s? Assume T = 20 °C .

A police car sounding a siren with a frequency of 1580 Hz is traveling at 120.0 km/h. The police car passes a car traveling in the same direction at 80.0 km/h. What two frequencies are heard in this car?

A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency will observers hear who are located, at rest, due south, of the whistle?

A factory whistle emits sound of frequency 770 Hz. The wind velocity is 15.0 m/s from the north (heading south). What frequency will observers hear who are located, at rest, due east, of the whistle?

A friend of yours is loudly singing a single note at 400 Hz while racing toward you at 25.0 m/s on a day when the speed of sound is 340 m/s. What frequency do you hear?

A battery-powered siren emits 0.50 W of sound power at 1000 Hz. It is dropped from 100 m directly over your head on a 20°C day. 4.0 s after it is released, what are (a) the frequency and (b) the sound intensity level you hear?

A physics professor demonstrates the Doppler effect by tying a 600 Hz sound generator to a 1.0-m-long rope and whirling it around her head in a horizontal circle at 100 rpm. What are the highest and lowest frequencies heard by a student in the classroom?

The spectrum of the sodium atom is detected in the light from a distant galaxy. If the $590.0$-nm line is redshifted to $658.5$ nm, at what speed is the galaxy receding from the earth?