Question 1

How fast (in m/s)is the Concorde moving if it reaches Mach 1.5? (The speed of sound in air is 344 m/s. )

Accepted Answer

A) 229 
B) 516 
C) 416 
D) 728 
E) 858 
A) 229 
B) 516 
C) 416 
D) 728 
E) 858

Question 2

If a supersonic plane is flying at increasing speed as the temperature decreases,what happens to the Mach number in this instance?

Accepted Answer

A) It stays the same. 
B) It increases. 
C) It decreases. 
D) It can do any of the above. 
E) It can do either (a)or (b)but not (c). 
A) It stays the same. 
B) It increases. 
C) It decreases. 
D) It can do any of the above. 
E) It can do either (a)or (b)but not (c).

Question 3

The velocity of sound in sea water is 1.53 × 103 m/s.Find the bulk modulus (in N/m2)of sea water if its density is 1.03 × 103 kg/m3.

Accepted Answer

A) 2.57 × 109 
B) 2.19 × 109 
C) 2.04 × 109 
D) 2.41 × 109 
E) 2.82 × 109 
A) 2.57 × 109 
B) 2.19 × 109 
C) 2.04 × 109 
D) 2.41 × 109 
E) 2.82 × 109

Question 4

The variation in the pressure of helium gas,measured from its equilibrium value,is given by ΔP = 2.9 × 10−5 cos (6.20x − 3 000t)where x and t have units m and s.Determine the speed (in m/s)of the wave.

Accepted Answer

A) 1 515 
B) 153 
C) 484 
D) 828 
E) 101 
A) 1 515 
B) 153 
C) 484 
D) 828 
E) 101

Question 5

On a day when the speed of sound in the upper air is 320 m/s,you fly coast to coast in the United States,a distance of about 4 850 km,in about one hour,if the Mach number for the speed of your airplane is about

Accepted Answer

A) 1. 
B) 2 
C) 3 
D) 4 
E) 5. 
A) 1. 
B) 2 
C) 3 
D) 4 
E) 5.

Question 6

A wave generated in a medium is a longitudinal wave when

Accepted Answer

A) there is a net transport of matter by the wave. 
B) the molecules of the medium are unable to exert forces on each other. 
C) molecular displacements are parallel to the wave velocity. 
D) molecular displacements are perpendicular to the wave velocity. 
E) the density of the medium is less than the density of water. 
A) there is a net transport of matter by the wave. 
B) the molecules of the medium are unable to exert forces on each other. 
C) molecular displacements are parallel to the wave velocity. 
D) molecular displacements are perpendicular to the wave velocity. 
E) the density of the medium is less than the density of water.

Question 7

A boy has climbed to the top of a 6.00 m tall tree.When he shouts,the sound waves have an intensity of  
At a 1.00 m distance from the top of the tree.The ratio of intensity at the base of the tree to the intensity 1.00 m from the top of the tree is

Accepted Answer

A)    . 
B)    . 
C)    . 
D)    . 
E)    . 
A)    . 
B)    . 
C)    . 
D)    . 
E)    .

Question 8

A jet plane has a sound level of 150 dB.What is the intensity in W/m2?

Accepted Answer

A) 1 
B) 100 
C) 10 
D) 1 000 
E) 10 000 
A) 1 
B) 100 
C) 10 
D) 1 000 
E) 10 000

Question 9

Determine the intensity (in W/m2)of a harmonic longitudinal wave with a pressure amplitude of 8.0 × 10−3 N/m2 propagating down a tube filled with helium.(ρ = 0.179 kg/m3,v = 972 m/s. )

Accepted Answer

A) 3.7 × 10−7 
B) 1.8 × 10−7 
C) 9.2 × 10−8 
D) 4.6 × 10−8 
E) 1.5 × 10−9 
A) 3.7 × 10−7 
B) 1.8 × 10−7 
C) 9.2 × 10−8 
D) 4.6 × 10−8 
E) 1.5 × 10−9

Question 10

By what factor will an intensity change when the corresponding sound level increases by 3 dB?

Accepted Answer

A) 3 
B) 0.5 
C) 2 
D) 4 
E) 0.3 
A) 3 
B) 0.5 
C) 2 
D) 4 
E) 0.3

Question 11

The fundamental frequency of a above middle C on the piano is 440 Hz.This is the tenor high A,but a convenient note in the mid-range of women's voices.When we calculate the wavelength,we find that it is

Accepted Answer

A) much shorter than the length of either a man's or woman's lips. 
B) shorter than the length of a man's lips,but about the length of a woman's lips. 
C) longer than a woman's lips,but about the length of a man's lips. 
D) much longer than the length of either a man's or a woman's lips. 
E) about the same length as either a man's or woman's lips. 
A) much shorter than the length of either a man's or woman's lips. 
B) shorter than the length of a man's lips,but about the length of a woman's lips. 
C) longer than a woman's lips,but about the length of a man's lips. 
D) much longer than the length of either a man's or a woman's lips. 
E) about the same length as either a man's or woman's lips.

Question 12

A truck moving at 36 m/s passes a police car moving at 45 m/s in the opposite direction.If the frequency of the siren relative to the police car is 500 Hz,what is the frequency heard by an observer in the truck as the police car approaches the truck? (The speed of sound in air is 343 m/s. )

Accepted Answer

A) 396 
B) 636 
C) 361 
D) 393 
E) 617 
A) 396 
B) 636 
C) 361 
D) 393 
E) 617

Question 13

A spherical wave has the form  
)
The frequency of the wave (in Hz)is

Accepted Answer

A) 3.68 × 10−4. 
B) 7.35 × 10−4. 
C) 1 360. 
D) 2 720. 
E) 2 720π. 
A) 3.68 × 10−4. 
B) 7.35 × 10−4. 
C) 1 360. 
D) 2 720. 
E) 2 720π.

Question 14

The variation in the pressure of helium gas,measured from its equilibrium value,is given by ΔP = 2.9 × 10−5 cos (6.20x − 3 000t)where x and t have units m and s,and ΔP is measured in N/m2.Determine the frequency (in Hz)of the wave.

Accepted Answer

A) 1 500 
B) 477 
C) 1.01 
D) 0.32 
E) 239 
A) 1 500 
B) 477 
C) 1.01 
D) 0.32 
E) 239

Question 15

A spherical wave has the form  
)
The amplitude of the wave a distance r from the source is

Accepted Answer

A) 0.002 cm. 
B)    . 
C)    . 
D)    . 
E)    . 
A) 0.002 cm. 
B)    . 
C)    . 
D)    . 
E)    .

Question 16

Which of the following does not have a precise definition in terms of the physical properties of sound waves?

Accepted Answer

A) frequency 
B) intensity 
C) loudness 
D) sound level 
E) wavelength 
A) frequency 
B) intensity 
C) loudness 
D) sound level 
E) wavelength

Question 17

When you hear the horn of a car that is approaching you,the frequency that you hear is larger than that heard by a person in the car because for the sound you hear

Accepted Answer

A) wave crests are farther apart by the distance the car travels in one period. 
B) wave crests are closer together by the distance the car travels in one period. 
C) the car gets ahead of each wave crest before it emits the next one. 
D) the speed of sound in air is increased by the speed of the car. 
E) a speeding car emits more wavecrests in each period. 
A) wave crests are farther apart by the distance the car travels in one period. 
B) wave crests are closer together by the distance the car travels in one period. 
C) the car gets ahead of each wave crest before it emits the next one. 
D) the speed of sound in air is increased by the speed of the car. 
E) a speeding car emits more wavecrests in each period.

Question 18

(Do not try the following: it could kill you.This question is only about a hypothetical possibility. )If you were standing below an object emitting a fixed frequency sound falling at terminal velocity,as it approached you,you would hear the sound

Accepted Answer

A) drop in frequency. 
B) stay at the same frequency. 
C) increase in frequency. 
D) decrease in loudness. 
E) stay at the same loudness. 
A) drop in frequency. 
B) stay at the same frequency. 
C) increase in frequency. 
D) decrease in loudness. 
E) stay at the same loudness.

Question 19

The intensity level of an orchestra is 85 dB.A single violin achieves a level of 70 dB.How does the intensity of the sound of the full orchestra compare with that of the violin?

Accepted Answer

The answer of The intensity level of an orchestra is...

Question 20

A speaker is producing 30 W of sound.At which of the following frequencies would it sound the loudest?

Accepted Answer

A) 50 Hz 
B) 100 Hz 
C) 500 Hz 
D) 1 000 Hz 
E) 10 000 Hz 
A) 50 Hz 
B) 100 Hz 
C) 500 Hz 
D) 1 000 Hz 
E) 10 000 Hz

Exam 17: Sound Waves

How fast (in m/s)is the Concorde moving if it reaches Mach 1.5? (The speed of sound in air is 344 m/s. )

If a supersonic plane is flying at increasing speed as the temperature decreases,what happens to the Mach number in this instance?

The velocity of sound in sea water is 1.53 × 103 m/s.Find the bulk modulus (in N/m2)of sea water if its density is 1.03 × 103 kg/m3.

The variation in the pressure of helium gas,measured from its equilibrium value,is given by ΔP = 2.9 × 10−5 cos (6.20x − 3 000t)where x and t have units m and s.Determine the speed (in m/s)of the wave.

On a day when the speed of sound in the upper air is 320 m/s,you fly coast to coast in the United States,a distance of about 4 850 km,in about one hour,if the Mach number for the speed of your airplane is about

A wave generated in a medium is a longitudinal wave when

A boy has climbed to the top of a 6.00 m tall tree.When he shouts,the sound waves have an intensity of At a 1.00 m distance from the top of the tree.The ratio of intensity at the base of the tree to the intensity 1.00 m from the top of the tree is

A jet plane has a sound level of 150 dB.What is the intensity in W/m2?

Determine the intensity (in W/m2)of a harmonic longitudinal wave with a pressure amplitude of 8.0 × 10−3 N/m2 propagating down a tube filled with helium.(ρ = 0.179 kg/m3,v = 972 m/s. )

By what factor will an intensity change when the corresponding sound level increases by 3 dB?

The fundamental frequency of a above middle C on the piano is 440 Hz.This is the tenor high A,but a convenient note in the mid-range of women's voices.When we calculate the wavelength,we find that it is

A truck moving at 36 m/s passes a police car moving at 45 m/s in the opposite direction.If the frequency of the siren relative to the police car is 500 Hz,what is the frequency heard by an observer in the truck as the police car approaches the truck? (The speed of sound in air is 343 m/s. )

A spherical wave has the form ) The frequency of the wave (in Hz)is

The variation in the pressure of helium gas,measured from its equilibrium value,is given by ΔP = 2.9 × 10−5 cos (6.20x − 3 000t)where x and t have units m and s,and ΔP is measured in N/m2.Determine the frequency (in Hz)of the wave.

A spherical wave has the form ) The amplitude of the wave a distance r from the source is

Which of the following does not have a precise definition in terms of the physical properties of sound waves?

When you hear the horn of a car that is approaching you,the frequency that you hear is larger than that heard by a person in the car because for the sound you hear

(Do not try the following: it could kill you.This question is only about a hypothetical possibility. )If you were standing below an object emitting a fixed frequency sound falling at terminal velocity,as it approached you,you would hear the sound

The intensity level of an orchestra is 85 dB.A single violin achieves a level of 70 dB.How does the intensity of the sound of the full orchestra compare with that of the violin?

A speaker is producing 30 W of sound.At which of the following frequencies would it sound the loudest?

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The velocity of sound in sea water is 1.53 × 10³ m/s.Find the bulk modulus (in N/m²)of sea water if its density is 1.03 × 10³ kg/m³.

The variation in the pressure of helium gas,measured from its equilibrium value,is given by ΔP = 2.9 × 10−⁵ cos (6.20x − 3 000t)where x and t have units m and s.Determine the speed (in m/s)of the wave.

A jet plane has a sound level of 150 dB.What is the intensity in W/m²?

Determine the intensity (in W/m²)of a harmonic longitudinal wave with a pressure amplitude of 8.0 × 10−³ N/m² propagating down a tube filled with helium.(ρ = 0.179 kg/m³,v = 972 m/s. )

The variation in the pressure of helium gas,measured from its equilibrium value,is given by ΔP = 2.9 × 10−⁵ cos (6.20x − 3 000t)where x and t have units m and s,and ΔP is measured in N/m².Determine the frequency (in Hz)of the wave.