Physics

2. a longitudinal wave created by
vibrating objects and capable
of producing a sensation in our
auditory system
is also referred as pressure
wave

3. 1. COMPRESSION
 are regions where density and pressure are higher than the
normal is produced
2. RAREFACTION
 region of decreased density and pressure

8. 1.Pitch
2.Loudness
3.Quality

9.  depends on the properties of the
medium to which the sound
propagates
 among the many properties of a
medium, the elastic property and
the inertial property of the
medium mainly affects the speed
of sound waves

10. √
elastic property
inertial property
V =

11. Sound travels fastest through solids.
 In fact, sound waves travel over 17 times
faster through steel than through air. The
exact speed of sound in steel is 5,960
meters per second (13,332 mph)!

12. YOUNG’S MODULUS (Y)
• named after Thomas Young
• is the ratio between the stress on the material
when force is applied and the resulting strain or
deformation
• The inertial property for solid materials is the
density ( )
• The SI unit for Young’s modulus is pascal (Pa) or
N/m2

13.  What is the speed of sound in
steel if the Young’s modulus of
the medium is 2.0 x 1011 N/m2
and its density is 7.8 x 103
kg/m3?

15. in fluids (liquids and gases), the speed of
sound is dependent on the bulk modulus of
the fluid and its density
the bulk modulus (B) is the ratio of the
intensity of stress to the volume strain
produced by the stress

16. What is the sound in water?
B = 2.1 x 109 N/m2
p = 1.0 x 102 kg/m3

19.  In gases (air), the speed of sound waves depending on the
temperature of gases.
 At 0˚C, the speed of sound is 331 m/s
 At temperatures higher than 0°C, the speed of sound is
computed as:
VT = V°C + (T)(0.6 m/s)
VT = 331 m/s + (T) (0.6 m/s)

20. How fast will sound travel in air that has a
temperature of 15O C?
VT = V°C + (T)(0.6 m/s)
or
VT = 330 m/s + (T) (0.6 m/s)
VT = 330 m/s + (15O C) (0.6 m/s)
VT = 339 m/s

23.  is the change in frequency of
a wave for an observer moving
relative to its source. It is
named after the Austrian
physicist Christian Doppler

30. Based on our definition, there IS
sound in the forest, whether a human
is there to hear it or not!.
Sound is a physical disturbance
in a medium.
A person to hear it is not required. The
medium (air) is required!

31. A sound wave is different than a light wave in that a
sound wave is
a. produced by a vibrating object and a light wave is not.
b. not capable of traveling through a vacuum.
c. not capable of diffracting and a light wave is.
d. capable of existing with a variety of frequencies and a
light wave has a single frequency.

32. A sound wave is a pressure wave; regions of high pressure
(compressions) and low pressure (rarefactions) are
established as the result of the vibrations of the sound
source. These compressions and rarefactions result
because sound
a. is more dense than air and thus has more inertia.
b. waves have a speed that is dependent only upon the
properties of the medium.
c. can be diffracted around obstacles.
d. vibrates longitudinally; the longitudinal movement of
air produces pressure fluctuations.