Calculating the speed of an approaching vehicle given the frequency of a car horn.

A student in a parked car honks the horn, which has a `proper' frequency of 300 Hz. An observer in an approaching vehicle measures the frequency of the sound to be 329 Hz. Calculate the speed of the approaching vehicle. Use 343 m/s as the speed of sound in air.

Working with velocity equations in a mechanical energy question.

The height of the upper falls at Yellowstone Falls is 33.2 m. When the water reaches the bottom of the falls, its speed is 25.8 m/s. Neglecting air resistance, what is the speed of the water at the top of the falls?

microphone in ocean

A microphone in the ocean is sensitive to sounds emitted by porpoises. To produce a usable signal, sound waves striking the microphone must have an intensity of 10.7 dB. If porpoises emit sound waves with a power of 0.0491 W, how far can a porpoise be from the microphone and still be heard? Disregard absorption of sound waves by the water.

Working with sound intensities.

A person standing a certain distance from an airplane with three equally noisy jet engines is feeling a sound level intensity bordering on pain, 120 dB. What sound level intensity (in dB) would this person experience if the captain shut down one engine?

guitar string

A particular guitar string is supposed to vibrate at 199.1 Hz, but it is measured to actually vibrate at 214.2 Hz. By what percent should the tension in the string be changed to cause the string to vibrate at the correct fundamental frequency? [Enter the percentage only; do not enter units.]