An oceanic depth-sounding vessel surveys the ocean bottom with ultrasonic waves that travel 1530 m/s in seawater. The time delay of the echo to the ocean floor and back is 6 s. Show that the depth of the water directly below the vessel is 4590 m.

A siren mounted 011 the roof of a firehouse emits sound at a frequency of 900 Hz. A steady wind is blowing with a speed of 15.0 m/s. Taking the speed of sound in calm air to be 343 m/s. find the wavelength of the sound (a) upwind of the siren and (b) downwind of the siren. Firefighters are approaching the siren from various directions at 15.0 m/s. What frequency does a firefighter hear (c) if she is approaching from an upwind position so that site is moving in the direction in which the wind is blowing and (d) if she is approaching from a downwind position and moving against the wind?

Submarine A travels horizontally at 11.0 m/s through ocean water. It emits a sonar signal of frequency f = 5.27 103 Hz in the forward direction. Submarine B is in front of submarine A and traveling at 3.00 m/s relative to the water in the same direction as submarine A. A crewman in submarine B uses his equipment to detect the sound waves (pings) from submarine A. We wish to determine what is heard by the crewman in submarine B. (a) An observer on which submarine detects a frequency f as described by Equation 16.46? (b) In Equation 16.46, should the sign of vs be positive or negative? (c) In Equation 16.46, should the sign of vo be positive or negative? (d) In Equation 16.46, what speed of sound should be used? (e) Find the frequency of the sound detected by the crewman on submarine B.

A wave on a string is driven by a string vibrator, which oscillates at a frequency of 100.00 Hz and an amplitude of 1.00 cm. The string vibrator operates at a voltage of 12.00 V and a current of 0.20 A. The power consumed by the string vibrator is P=IV . Assume that the string vibrator is 90% efficient at converting electrical energy into the energy associated with the vibrations of the string. The string is 3.00 m long, and is under a tension of 60.00 N. What is the linear mass density of the string?

Problems 32 and 33 are paired. N Seismic waves travel outward from the epicenter of an earthquake. A single earthquake produces both longitudinal seismic waves known as P waves and transverse waves known as S waves. Both transverse and longitudinal waves can travel through solids such as rock. Longitudinal waves can travel through fluids, whereas transverse waves can only be sustained near the surface of a fluid, not inside the fluid. When seismic waves encounter a fluid medium such as the liquid outer core of the Earth, only the longitudinal P wave can propagate through. Geophysicists can model the interior of the Earth by knowing where and when S and P waves were detected by seismographs after an earthquake (Fig. P17.32). Assume the average speed of an S wave through the Earths mantle is 5.4 km/s and the average speed of a P wave is 9.3 km/s. After an earthquake, a seismograph finds that the P wave arrives 1.5 min before the S wave. How far is the epicenter from the detector? FIGURE P17.32

A yellow submarine traveling horizontally at 11.0 m/s uses sonar with a frequency of 5.27 103 Hz. A red submarine is in front of the yellow submarine and moving 3.00 m/s relative to the water in the same direction. A crewman in the red submarine observes sound waves (pings) from the yellow submarine. Take the speed of sound in seawater as 1 533 m/s. (a) Write Equation 14.12. (b) Which submarine is the source of the sound? (c) Which submarine carries the observer? (d) Does the motion of the observers submarine increase or decrease the time between the pressure maxima of the incoming sound waves? How does that affect the observed period? The observed frequency? (e) Should the sign of v0 be positive or negative? (f) Does the motion of the source submarine increase or decrease the time observed between the pressure maxima? How does this motion affect the observed period? The observed frequency? (g) What sign should be chosen for vs? (h) Substitute the appropriate numbers and obtain the frequency observed by the crewman on the red submarine.

A dolphin (Fig. P17.7) in seawater at a temperature of 25C emits a sound wave directed toward the ocean floor 150 m below. How much time passes before it hears an echo?

You are working as an assistant to a landscape architect. who is designing the landscaping around a new commercial building. The architect plans to have a large rectangular water basin as part of his design. When you see this design, you mention to the architect that the project is located in an area prone to earthquakes. You point out that an earthquake could create a seiche in the basin by resonance, causing the water in the basin to spill out and enter nearby underground electrical transformers. A seiche is a standing wave in a body of water, in which the water sloshes back and forth with antinodes at the ends of the basin. (You may have created a seiche in a bathtub as a child by sliding your body back and forth along the length of the tub, leaving water on the floor for your parents to wipe up.) The architect dismisses your comments as unrealistic. While visiting your cousin the previous week in a non-carthquake-prone area, you had seen a water basin similar to the one planned by the architect. You call your cousin and find out that the water basin in his town has the same depth of water as that planned by the architect. You ask your cousin to create a pulse in the water by dropping a pebble, and determine how long the pulse takes to cross the basin. Based on this time interval and the length of your cousins basin, you determine that a pulse will take 2.50 s to cross the basin planned by the architect. Show the architect that there will be several possible seiche resonances in the water basin for typical low frequencies of earthquakes in the range of 04 Hz.

Review. A tuning fork vibrating at 512 Hz falls from rest and accelerates at 9.80 m/s2. How far below the point of release is the tuning fork when waves of frequency 485 Hz reach the release point?

Earthquakes at fault lines in the Earths crust create seismic waves, which are longitudinal (P waves) or transverse (S waves). The P waves have a speed of about 7 km/s. Estimate the average bulk modulus of the Earths crust given that the density of rock is about 2 500 kg/m3.