(speed of sound).
In air at 20ЊC, the speed of sound is 343 m/s.
v ϭ A
B
479
What Is Physics?
The physics of sound waves is the basis of countless studies in the research
journals of many fields. Here are just a few examples. Some physiologists are
concerned with how speech is produced, how speech impairment might be
corrected, how hearing loss can be alleviated, and even how snoring is produced. Some acoustic engineers are concerned with improving the acoustics of
cathedrals and concert halls, with reducing noise near freeways and road
construction, and with reproducing music by speaker systems. Some aviation engineers are concerned with the shock waves produced by supersonic aircraft and
the aircraft noise produced in communities near an airport. Some medical researchers are concerned with how noises produced by the heart and lungs can
signal a medical problem in a patient. Some paleontologists are concerned with
how a dinosaur’s fossil might reveal the dinosaur’s vocalizations. Some military
engineers are concerned with how the sounds of sniper fire might allow a soldier to pinpoint the sniper’s location, and, on the gentler side, some biologists are concerned with how a cat purrs.
To begin our discussion of the physics of sound, we must first answer the
question “What are sound waves?”
Sound Waves
As we saw in Chapter 16, mechanical waves are waves that require a material
medium to exist. There are two types of mechanical waves: Transverse waves
involve oscillations perpendicular to the direction in which the wave travels;
longitudinal waves involve oscillations parallel to the direction of wave travel.
In this book, a sound wave is defined roughly as any longitudinal wave.
Seismic prospecting teams use such waves to probe Earth’s crust for oil. Ships
C
H
A
P
T
E
R
1 7
Waves—II
17-1 SPEED OF SOUND
After reading this module, you should be able to . . .
17.01 Distinguish between a longitudinal wave and a
transverse wave.
17.02 Explain wavefronts and rays.
17.03 Apply the relationship between the speed of sound
through a material, the material’s bulk modulus, and the
material’s density.
Key Idea
Learning Objectives
● Sound waves are longitudinal mechanical waves that can
travel through solids, liquids, or gases. The speed v of a
sound wave in a medium having bulk modulus B and density r is
17.04 Apply the relationship between the speed of sound, the
distance traveled by a sound wave, and the time required
to travel that distance.
In air at 20ЊC, the speed of sound is 343 m/s.
v ϭ A
B
479
What Is Physics?
The physics of sound waves is the basis of countless studies in the research
journals of many fields. Here are just a few examples. Some physiologists are
concerned with how speech is produced, how speech impairment might be
corrected, how hearing loss can be alleviated, and even how snoring is produced. Some acoustic engineers are concerned with improving the acoustics of
cathedrals and concert halls, with reducing noise near freeways and road
construction, and with reproducing music by speaker systems. Some aviation engineers are concerned with the shock waves produced by supersonic aircraft and
the aircraft noise produced in communities near an airport. Some medical researchers are concerned with how noises produced by the heart and lungs can
signal a medical problem in a patient. Some paleontologists are concerned with
how a dinosaur’s fossil might reveal the dinosaur’s vocalizations. Some military
engineers are concerned with how the sounds of sniper fire might allow a soldier to pinpoint the sniper’s location, and, on the gentler side, some biologists are concerned with how a cat purrs.
To begin our discussion of the physics of sound, we must first answer the
question “What are sound waves?”
Sound Waves
As we saw in Chapter 16, mechanical waves are waves that require a material
medium to exist. There are two types of mechanical waves: Transverse waves
involve oscillations perpendicular to the direction in which the wave travels;
longitudinal waves involve oscillations parallel to the direction of wave travel.
In this book, a sound wave is defined roughly as any longitudinal wave.
Seismic prospecting teams use such waves to probe Earth’s crust for oil. Ships
C
H
A
P
T
E
R
1 7
Waves—II
17-1 SPEED OF SOUND
After reading this module, you should be able to . . .
17.01 Distinguish between a longitudinal wave and a
transverse wave.
17.02 Explain wavefronts and rays.
17.03 Apply the relationship between the speed of sound
through a material, the material’s bulk modulus, and the
material’s density.
Key Idea
Learning Objectives
● Sound waves are longitudinal mechanical waves that can
travel through solids, liquids, or gases. The speed v of a
sound wave in a medium having bulk modulus B and density r is
17.04 Apply the relationship between the speed of sound, the
distance traveled by a sound wave, and the time required
to travel that distance.