University Physics Volume 1
18th Edition
ISBN: 9781938168277
Author: William Moebs, Samuel J. Ling, Jeff Sanny
Publisher: OpenStax - Rice University
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Textbook Question
Chapter 17, Problem 72P
Loudspeakers can produce intense sounds with surprisingly small energy input in spite of their low efficiencies. Calculate the power input needed to produce a 90.0-dB sound intensity level for a 12.0-cm-diameter speaker that has an efficiency of 1.00% . (This value is the sound intensity level right at the speaker.)
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Chapter 17 Solutions
University Physics Volume 1
Ch. 17 - Check Your Understanding Imagine you observe two...Ch. 17 - Check Your Understanding Identify common sounds at...Ch. 17 - Check Your Understanding Describe how amplitude is...Ch. 17 - Check Your Understanding If you walk around two...Ch. 17 - Check Your Understanding Describe how...Ch. 17 - Check Your Understanding How is it possible to use...Ch. 17 - Check Your Understanding You observe two musical...Ch. 17 - Check Your Understanding What would happen if more...Ch. 17 - Check Your Understanding Describe a situation in...Ch. 17 - What is the difference between sound and hearing?
Ch. 17 - You will learn that light is an electromagnetic...Ch. 17 - Sound waves can be modeled as a change in...Ch. 17 - How do sound vibrations of atoms differ from...Ch. 17 - When sound passes from one medium to another where...Ch. 17 - A popular party trick is to inhale helium and...Ch. 17 - You may have used a sonic range finder in lab to...Ch. 17 - The sonic range finder discussed in the preceding...Ch. 17 - Six members of a synchronized swim team wear...Ch. 17 - A community is concerned about a plan to bring...Ch. 17 - You are given two wind instruments of identical...Ch. 17 - What is the difference between an overtone and a...Ch. 17 - Two identical columns, open at both ends, are in...Ch. 17 - How does an unamplified guitar produce sounds so...Ch. 17 - Consider three pipes of the same length (L). Pipe...Ch. 17 - Pipe A has a length L and is open at both ends....Ch. 17 - A string is tied between two lab posts a distance...Ch. 17 - Two speakers are attached to variable-frequency...Ch. 17 - The label has been scratched off a tuning fork and...Ch. 17 - Referring to the preceding question, if you had...Ch. 17 - A “showy” custom-built car has two brass horns...Ch. 17 - Is the Doppler shift real or just a sensory...Ch. 17 - Three stationary observers observe the Doppler...Ch. 17 - Shown below is a stationary source and moving...Ch. 17 - Prior to 1980, conventional radar was used by...Ch. 17 - What is the difference between a sonic boom and a...Ch. 17 - Due to efficiency considerations related to its...Ch. 17 - When you hear a sonic boom, you often cannot see...Ch. 17 - Consider a sound wave modeled with the equation...Ch. 17 - Consider a sound wave moving through the air...Ch. 17 - Consider a diagnostic ultrasound of frequency 5.00...Ch. 17 - A sound wave is modeled as...Ch. 17 - A sound wave is modeled with the wave function...Ch. 17 - The displacement of the air molecules in sound...Ch. 17 - A speaker is placed at the opening of a long...Ch. 17 - A 250-Hz tuning fork is struck and begins to...Ch. 17 - A sound wave produced by an ultrasonic transducer,...Ch. 17 - Porpoises emit sound waves that they use for...Ch. 17 - Bats use sound waves to catch insects. Bats can...Ch. 17 - A bat sends of a sound wave 100 kHz and the sound...Ch. 17 - Consider the graph shown below of a compression...Ch. 17 - Consider the graph in the preceding problem of a...Ch. 17 - A guitar string oscillates at a frequency of 100...Ch. 17 - When poked by a spear, an operatic soprano lets...Ch. 17 - What frequency sound has a 0.10-m wavelength when...Ch. 17 - Calculate the speed of sound on a day when a...Ch. 17 - (a) What is the speed of sound in a medium where a...Ch. 17 - Show that the speed of sound in 20.0°C air is 343...Ch. 17 - Air temperature in the Sahara Desert can reach...Ch. 17 - Dolphins make sounds in air and water. What is the...Ch. 17 - A sonar echo returns to a submarine 1.20 s after...Ch. 17 - (a) If a submarine’s sonar can measure echo times...Ch. 17 - Ultrasonic sound waves are often used in methods...Ch. 17 - A physicist at a fireworks display times the lag...Ch. 17 - During a 4th of July celebration, an M80 firework...Ch. 17 - The density of a sample of water is =998.00kg/m3...Ch. 17 - Suppose a bat uses sound echoes to locate its...Ch. 17 - What is the intensity in watts per meter squared...Ch. 17 - The warning tag on a lawn mower states that it...Ch. 17 - A sound wave traveling in air has a pressure...Ch. 17 - What intensity level does the sound in the...Ch. 17 - What sound intensity level in dB is produced by...Ch. 17 - What is the decibel level of a sound that is twice...Ch. 17 - What is the intensity of a sound that has a level...Ch. 17 - People with good hearing can perceive sounds as...Ch. 17 - If a large housefly 3.0 m away from you makes a...Ch. 17 - Ten cars in a circle at a boom box competition...Ch. 17 - The amplitude of a sound wave is measured in terms...Ch. 17 - If a sound intensity level of 0 dB at 1000 Hz...Ch. 17 - An 8-hour exposure to a sound intensity level of...Ch. 17 - Sound is more effectively transmitted into a...Ch. 17 - Loudspeakers can produce intense sounds with...Ch. 17 - The factor of 10-12 in the range of intensities to...Ch. 17 - What are the closest frequencies to 500 Hz that an...Ch. 17 - YY13Can you tell that your roommate turned up the...Ch. 17 - If a woman needs an amplification of 5.0105 times...Ch. 17 - A person has a hearing threshold 10 dB above...Ch. 17 - (a) What is the fundamental frequency of a...Ch. 17 - What is the length of a tube that has a...Ch. 17 - The ear canal resonates like a tube closed at one...Ch. 17 - Calculate the first overtone in an ear canal,...Ch. 17 - A crude approximation of voice production is to...Ch. 17 - A 4.0-m-long pipe, open at one end and closed at...Ch. 17 - A 4.0-m-long pipe, open at both ends, is placed in...Ch. 17 - A nylon guitar string is fixed between two lab...Ch. 17 - A 512-Hz tuning fork is struck and placed next to...Ch. 17 - Students in a physics lab are asked to find the...Ch. 17 - If a wind instrument, such as a tuba, has a...Ch. 17 - What are the first three overtones of a bassoon...Ch. 17 - How long must a flute be in order to have a...Ch. 17 - What length should an oboe have to produce a...Ch. 17 - (a) Find the length of an organ pipe closed at one...Ch. 17 - An organ pipe (L=3.00m) is closed at both ends....Ch. 17 - An organ pipe (L=3.00m) is closed at one end....Ch. 17 - A sound wave of a frequency of 2.00 kHz is...Ch. 17 - Consider the sound created by resonating the tube...Ch. 17 - A student holds an 80.00-cm lab pole one quarter...Ch. 17 - A string on the violin has a length of 24.00 cm...Ch. 17 - By what fraction will the frequencies produced by...Ch. 17 - What beat frequencies are present: (a) If the...Ch. 17 - What beat frequencies result if a piano hammer...Ch. 17 - A piano tuner hears a beat every 2.00 s when...Ch. 17 - Two identical strings, of identical lengths of...Ch. 17 - A piano tuner uses a 512-Hz tuning fork to tune a...Ch. 17 - A string with a linear mass density of =0.0062...Ch. 17 - A car has two horns, one emitting a frequency of...Ch. 17 - The middle C hammer of a piano hits two strings,...Ch. 17 - Two tuning forks having frequencies of 460 and 464...Ch. 17 - Twin jet engines on an airplane are producing an...Ch. 17 - Three adjacent keys on a piano (F, F-sharp, and G)...Ch. 17 - (a) What frequency is received by a person...Ch. 17 - (a) At an air show a jet flies directly toward the...Ch. 17 - What frequency is received by a mouse just before...Ch. 17 - A spectator at a parade receives an 888-Hz tone...Ch. 17 - A commuter train blows its 200-Hz horn as it...Ch. 17 - Can you perceive the shift in frequency produced...Ch. 17 - Two eagles fly directly toward one another, the...Ch. 17 - Student A runs down the hallway of the school at a...Ch. 17 - An ambulance with a siren (f=1.00kHz) blaring is...Ch. 17 - The frequency of the siren of an ambulance is 900...Ch. 17 - What is the minimum speed at which a source must...Ch. 17 - An airplane is flying at Mach 1.50 at an altitude...Ch. 17 - A jet flying at an altitude of 8.50 km has a speed...Ch. 17 - The shock wave off the front of a fighter jet has...Ch. 17 - A plane is flying at Mach 1.2, and an observer on...Ch. 17 - A bullet is fired and moves at a speed of 1342...Ch. 17 - A speaker is placed at the opening of a long...Ch. 17 - An airplane moves at Mach 1.2 and produces a shock...Ch. 17 - A 0.80-m-long tube is opened at both ends. The air...Ch. 17 - A tube filled with water has a valve at the bottom...Ch. 17 - Consider the following figure. The length of the...Ch. 17 - Early Doppler shift experiments were conducted...Ch. 17 - Two cars move toward one another, both sounding...Ch. 17 - Student A runs after Student B. Student A carries...Ch. 17 - Suppose that the sound level from a source is 75...Ch. 17 - The Doppler shift for a Doppler radar is found by...Ch. 17 - A stationary observer hears a frequency of 1000.00...Ch. 17 - A flute plays a note with a frequency of 600 Hz....Ch. 17 - Two sound speakers are separated by a distance d,...Ch. 17 - Consider the beats shown below. This is a graph of...Ch. 17 - Two speakers producing the same frequency of sound...Ch. 17 - A string has a length of 1.5 m, a linear mass...Ch. 17 - A string (=0.006kgm,L=1.50m) is fixed at both ends...Ch. 17 - A string has a linear mass density µ, a length L,...Ch. 17 - A string has a linear mass density =0.007 kg/m, a...Ch. 17 - A speaker powered by a signal generator is used to...Ch. 17 - A string on the violin has a length of 23.00 cm...
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