Question 1

In the figure,which of the curves best represents the variation of wave speed as a function of tension for transverse waves on a stretched string?

Accepted Answer

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

Question 2

A transverse wave is traveling on a string stretched along the horizontal x-axis.The equation for the vertical displacement y of the string is given by y = 0.0020 cos[π(15x - 52t)],where all quantities are in SI units.The maximum speed of a particle of the string is closest to

Accepted Answer

A) 0.33 m/s. 
B) 0.43 m/s. 
C) 0.53 m/s. 
D) 0.64 m/s. 
E) 0.74 m/s. 
A) 0.33 m/s. 
B) 0.43 m/s. 
C) 0.53 m/s. 
D) 0.64 m/s. 
E) 0.74 m/s.

Question 3

A sound source emits 20.0 W of acoustical power spread equally in all directions.The threshold of hearing is 1.0 × 10-12 W/m2.What is the sound intensity level 30.0 m from the source?

Accepted Answer

A) 92.5 dB 
B) 81.5 dB 
C) 1.77 × 10-3 dB 
D) 1.77 × 10-3 W 
E) -27.5 dB 
A) 92.5 dB 
B) 81.5 dB 
C) 1.77 × 10-3 dB 
D) 1.77 × 10-3 W 
E) -27.5 dB

Question 4

The intensity level of a "Super-Silent" power lawn mower at a distance of 1.0 m is 100 dB.You wake up one morning to find that four of your neighbors are all mowing their lawns using identical "Super-Silent" mowers.When they are each 20 m from your open bedroom window,what is the intensity level of the sound in your bedroom? You can neglect any absorption,reflection,or interference of the sound.The lowest detectable intensity is 1.0 × 10-12 W/m2.

Accepted Answer

A) 80 dB 
B) 104 dB 
C) 400 dB 
D) 50 dB 
E) 40 dB 
A) 80 dB 
B) 104 dB 
C) 400 dB 
D) 50 dB 
E) 40 dB

Question 5

A heavy stone of mass m is hung from the ceiling by a thin 8.25-g wire that is 65.0 cm long.When you gently pluck the upper end of the wire,a pulse travels down the wire and returns 7.84 ms later,having reflected off the lower end.The stone is heavy enough to prevent the lower end of the wire from moving.What is the mass m of the stone?

Accepted Answer

A) 8.90 kg 
B) 23.1 kg 
C) 35.6 kg 
D) 227 kg 
E) 349 kg 
A) 8.90 kg 
B) 23.1 kg 
C) 35.6 kg 
D) 227 kg 
E) 349 kg

Question 6

A certain crying baby emits sound with an intensity of 8.0 × 10-8 W/m2.What is the intensity level due to a set of five such crying babies,all crying with the same intensity? You can neglect any absorption,reflection,or interference of the sound.The lowest detectable intensity is 1.0 × 10-12 W/m2.

Accepted Answer

A) 79 dB 
B) 69 dB 
C) 56 dB 
D) 49 dB 
E) 36 dB 
A) 79 dB 
B) 69 dB 
C) 56 dB 
D) 49 dB 
E) 36 dB

Question 7

As you stand by the side of the road,a car approaches you at a constant speed,sounding its horn,and you hear a frequency of 80.0 Hz.After the car goes by,you hear a frequency of 60.0 Hz.What is the speed of the car? The speed of sound in the air is 343 m/s.

Accepted Answer

A) 64.0 m/s 
B) 49.0 m/s 
C) 16.0 m/s 
D) 36.0 m/s 
E) 25.0 m/s 
A) 64.0 m/s 
B) 49.0 m/s 
C) 16.0 m/s 
D) 36.0 m/s 
E) 25.0 m/s

Question 8

The speed of sound in the air inside a 0.640-m long gas column is 340 m/s.What is the fundamental resonant frequency of this air column if it is
(a)open at one end and closed at the other end?
(b)open at both ends?

Accepted Answer

The answer of The speed of sound in the air...

Question 9

Which one of the following statements is true?

Accepted Answer

A) Both the intensity level (in d
B) and the sound intensity can never be negative. 
B) The intensity level (in d
B) obeys an inverse-square distance law,but the sound intensity does not. 
C) Both intensity level (in d
B) and sound intensity obey inverse-square distance laws. 
D) The sound intensity can never be negative,but the intensity level (in d
B) can be negative. 
E) Both the intensity level (in d
B) and the sound intensity can be negative. 
A) Both the intensity level (in d
B) and the sound intensity can never be negative. 
B) The intensity level (in d
B) obeys an inverse-square distance law,but the sound intensity does not. 
C) Both intensity level (in d
B) and sound intensity obey inverse-square distance laws. 
D) The sound intensity can never be negative,but the intensity level (in d
B) can be negative. 
E) Both the intensity level (in d
B) and the sound intensity can be negative.

Question 10

The figure shows the displacement y of a traveling wave at a given position as a function of time and the displacement of the same wave at a given time as a function of position.Determine the wavelength of the wave.

Accepted Answer

A) 2.0 cm 
B) 3.0 m 
C) 2.0 m 
D) 4.0 m 
E) 1.5 m 
A) 2.0 cm 
B) 3.0 m 
C) 2.0 m 
D) 4.0 m 
E) 1.5 m

Question 11

Four traveling waves are described by the following equations,where all quantities are measured in SI units and y represents the displacement. I: y = 0.12 cos(3x - 21t)
II: y = 0.15 sin(6x + 42t)
III: y = 0.13 cos(6x + 21t)
IV: y = -0.27 sin(3x - 42t)
Which of these waves have the same period?

Accepted Answer

A) I and III,and also II and IV 
B) I and IV,and also II and III 
C) I and II,and also III and IV 
D) All of them have the same period. 
E) They all have different periods. 
A) I and III,and also II and IV 
B) I and IV,and also II and III 
C) I and II,and also III and IV 
D) All of them have the same period. 
E) They all have different periods.

Question 12

Observer A is 3.0 m from a tiny light bulb and observer B is 12.0 m from the same bulb.Assume that the light spreads out uniformly and undergoes no significant reflections or absorption.If observer B sees a light of intensity I,the light intensity that A sees is

Accepted Answer

A) I. 
B) 9I. 
C) 16I. 
D) 36I. 
E) 144I. 
A) I. 
B) 9I. 
C) 16I. 
D) 36I. 
E) 144I.

Question 13

You and your surfing buddy are waiting to catch a wave a few hundred meters off the beach.The waves are conveniently sinusoidal,and you notice that when you're on the top of one wave and moving toward your friend,she is exactly halfway between you and the trough of the wave.1.50 seconds later,your friend is at the top of the wave.You estimate the horizontal distance between you and your friend at 8.00 m.
(a)What is the frequency of the waves?
(b)Find the speed of the waves.

Accepted Answer

(a)0.167 H

Question 14

The figure shows the displacement y of a wave at a given position as a function of time and the displacement of the same wave at a given time as a function of position.Determine the frequency of the wave.

Accepted Answer

A) 4.0 Hz 
B) 0.50 Hz 
C) 3.0 Hz 
D) 0.33 Hz 
E) 0.25 Hz 
A) 4.0 Hz 
B) 0.50 Hz 
C) 3.0 Hz 
D) 0.33 Hz 
E) 0.25 Hz

Question 15

A 6.0-m wire with a mass of 50 g,is under tension.A transverse wave,for which the frequency is 810 Hz,the wavelength is 0.40 m,and the amplitude is 4.0 mm,is propagating on the wire.The time for a crest of this wave to travel the length of the wire is closest to

Accepted Answer

A) 19 ms. 
B) 16 ms. 
C) 21 ms. 
D) 23 ms. 
E) 25 ms. 
A) 19 ms. 
B) 16 ms. 
C) 21 ms. 
D) 23 ms. 
E) 25 ms.

Question 16

The intensity of sunlight falling on the earth is about 1.4 kW/m2 (before any gets absorbed by our atmosphere).At what rate does the sun emit light energy? (The earth-sun distance = 1.5 × 108 km and the earth's radius = 6.4 × 103 km.)

Accepted Answer

A) 4.0 × 1026 W 
B) 3.2 × 1022 W 
C) 7.2 × 1014 W 
D) 7.6 × 108 W 
A) 4.0 × 1026 W 
B) 3.2 × 1022 W 
C) 7.2 × 1014 W 
D) 7.6 × 108 W

Question 17

The vertical displacement y(x,t)of a string stretched along the horizontal x-axis is given by y(x,t)= (6.00 mm)cos[(3.25 m-1)x - (7.22 rad/s)t].
(a)What is the minimum time for each complete cycle of the wave?
(b)What is the distance between adjacent crests of the wave?
(c)How fast does this wave travel?

Accepted Answer

(a)0.870 s

Question 18

When a weight W is hanging from a light vertical string,the speed of pulses on the string is V.If a second weight W is added without stretching the string,the speed of pulses on this string will now become

Accepted Answer

A) 2V. 
B)    V. 
C) V. 
D) V/   . 
E) V/2 
A) 2V. 
B)    V. 
C) V. 
D) V/   . 
E) V/2

Question 19

You are generating traveling waves on a stretched string by wiggling one end.If you suddenly begin to wiggle more rapidly without appreciably affecting the tension,you will cause the waves to move down the string

Accepted Answer

A) faster than before. 
B) slower than before. 
C) at the same speed as before. 
A) faster than before. 
B) slower than before. 
C) at the same speed as before.

Question 20

For the wave shown in the figure,the wavelength is

Accepted Answer

A) 8 m. 
B) 4 m. 
C) 2 m. 
D) 1 m. 
E) unable to be determined from the given information. 
A) 8 m. 
B) 4 m. 
C) 2 m. 
D) 1 m. 
E) unable to be determined from the given information.

Exam 16: Traveling Waves

In the figure,which of the curves best represents the variation of wave speed as a function of tension for transverse waves on a stretched string?

A transverse wave is traveling on a string stretched along the horizontal x-axis.The equation for the vertical displacement y of the string is given by y = 0.0020 cos[π(15x - 52t)],where all quantities are in SI units.The maximum speed of a particle of the string is closest to

A sound source emits 20.0 W of acoustical power spread equally in all directions.The threshold of hearing is 1.0 × 10-12 W/m2.What is the sound intensity level 30.0 m from the source?

As you stand by the side of the road,a car approaches you at a constant speed,sounding its horn,and you hear a frequency of 80.0 Hz.After the car goes by,you hear a frequency of 60.0 Hz.What is the speed of the car? The speed of sound in the air is 343 m/s.

The speed of sound in the air inside a 0.640-m long gas column is 340 m/s.What is the fundamental resonant frequency of this air column if it is (a)open at one end and closed at the other end? (b)open at both ends?

Which one of the following statements is true?

The figure shows the displacement y of a traveling wave at a given position as a function of time and the displacement of the same wave at a given time as a function of position.Determine the wavelength of the wave.

Four traveling waves are described by the following equations,where all quantities are measured in SI units and y represents the displacement. I: y = 0.12 cos(3x - 21t) II: y = 0.15 sin(6x + 42t) III: y = 0.13 cos(6x + 21t) IV: y = -0.27 sin(3x - 42t) Which of these waves have the same period?

Observer A is 3.0 m from a tiny light bulb and observer B is 12.0 m from the same bulb.Assume that the light spreads out uniformly and undergoes no significant reflections or absorption.If observer B sees a light of intensity I,the light intensity that A sees is

The figure shows the displacement y of a wave at a given position as a function of time and the displacement of the same wave at a given time as a function of position.Determine the frequency of the wave.

A 6.0-m wire with a mass of 50 g,is under tension.A transverse wave,for which the frequency is 810 Hz,the wavelength is 0.40 m,and the amplitude is 4.0 mm,is propagating on the wire.The time for a crest of this wave to travel the length of the wire is closest to

The intensity of sunlight falling on the earth is about 1.4 kW/m2 (before any gets absorbed by our atmosphere).At what rate does the sun emit light energy? (The earth-sun distance = 1.5 × 108 km and the earth's radius = 6.4 × 103 km.)

When a weight W is hanging from a light vertical string,the speed of pulses on the string is V.If a second weight W is added without stretching the string,the speed of pulses on this string will now become

You are generating traveling waves on a stretched string by wiggling one end.If you suddenly begin to wiggle more rapidly without appreciably affecting the tension,you will cause the waves to move down the string

For the wave shown in the figure,the wavelength is

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A sound source emits 20.0 W of acoustical power spread equally in all directions.The threshold of hearing is 1.0 × 10^-12 W/m².What is the sound intensity level 30.0 m from the source?

The intensity of sunlight falling on the earth is about 1.4 kW/m² (before any gets absorbed by our atmosphere).At what rate does the sun emit light energy? (The earth-sun distance = 1.5 × 10⁸ km and the earth's radius = 6.4 × 10³ km.)