Question 1

The fundamental frequency of a vibrating string is f1. If the tension in the string is increased by 50% while the linear density is held constant, the fundamental frequency becomes

Accepted Answer

A)   f1. 
B)   1.2f1. 
C)   1.5f1. 
D)   1.7f1. 
E)   2f1. F) C) and E)
G) B) and D)

Question 2

The graph shows a wave moving from left to right. If the period of this wave motion is 50 m/s, the wave is moving with a velocity of

Accepted Answer

A)   40 π cm/s.
B)   1.6 π m/s.
C)   1.6 m/s.
D)   80 cm/s.
E)   0.40 cm/s.F) D) and E)
G) B) and E)

Question 3

Which of the following wavefronts results from a supersonic flight?

Accepted Answer

A)   1) 
B)   2) 
C)   3) 
D)   1)  and 3) 
E)   They are all supersonic.F) B) and D)
G) A) and D)

Question 4

For a tube of length 57.0 cm that is open at both ends, what is the frequency of the fundamental mode? The speed of sound in air is 340 m/s.)

Accepted Answer

A)   149 Hz
B)   447 Hz
C)   596 Hz
D)   298 Hz
E)   746 HzF) B) and C)
G) A) and E)

Question 5

A pulse moves in a string toward a free end a ring on a post)  as indicated in the sketch. On reflection, the pulse would most nearly be represented by

Accepted Answer

A)   1.
B)   2.
C)   3.
D)   4.
E)   5.F) C) and E)
G) None of the above

Question 6

The frequency of a car horn is f. What frequency is observed if both the car and the observer are at rest, but a wind is blowing toward the observer?

Accepted Answer

A)   f
B)   greater than f
C)   less than f
D)   either greater or less than f
E)   far greater than f, depending on how wind speed compares with the speed of soundF) B) and C)
G) B) and E)

Question 7

Car A moves at speed v toward car B, which is at rest. The frequency of car A's horn is observed by car B to be f. What is the frequency of car A's horn as heard by an observer in car B if car A is at rest and car B moves at speed v toward car A assume there is no wind) ?

Accepted Answer

A)   f
B)   greater than f
C)   less than f
D)   either greater than or less than f
E)   2fF) A) and B)
G) A) and C)

Question 8

A string 2.0 m long has a mass of 2.4  10-2 kg. When fixed at both ends, it vibrates with a fundamental frequency of 150 Hz. The speed of a transverse wave in the string is

Accepted Answer

A)   3.6 m/s.
B)   75 m/s.
C)   0.30 km/s.
D)   0.60 km/s.
E)   0.63 km/s.F) A) and B)
G) C) and D)

Question 9

A sinusoidal wave train is moving along a string. The equation giving the displacement y of a point at coordinate x has the form where the units are SI. The wavelength is

Accepted Answer

A)   8.0 cm.
B)   15 cm.
C)   6.0 m.
D)   12 m.
E)   60 m.F) A) and B)
G) C) and E)

Question 10

If you were to double the speed of a wave on a string while keeping the frequency and amplitude of the wave constant, the rate at which energy is delivered by the wave would

Accepted Answer

A)   double.
B)   quadruple.
C)   be reduced 50%.
D)   be reduced to 25% of its previous value.
E)   be unchanged.F) A) and B)
G) A) and E)

Question 11

To double the rate at which energy is transmitted along a string, you could

Accepted Answer

A)   double the angular frequency of the source.
B)   double the amplitude of the wave.
C)   double the tension in the string.
D)   quadruple the tension in the string.
E)   halve the linear density of the string.F) A) and C)
G) C) and D)

Question 12

When an organ pipe, which is closed at one end only, vibrates with a frequency that is 3 times its fundamental first harmonic)  frequency,

Accepted Answer

A)   the sound produced travels at 3 times its former speed.
B)   the sound produced is its fifth harmonic.
C)   beats are produced.
D)   the sound produced has one-third its former wavelength.
E)   the closed end is a displacement antinode.F) A) and B)
G) A) and C)

Question 13

During the passage of a longitudinal wave, a particle of the medium

Accepted Answer

A)   remains in a fixed position.
B)   moves in a circle.
C)   moves at right angles to the direction of propagation.
D)   moves forward and backward along the line of propagation.
E)   moves forward with the velocity of the wave.F) A) and C)
G) C) and D)

Question 14

The fundamental frequency of a vibrating string is f1. If the tension in the string is quadrupled while the linear density is held constant, the fundamental frequency becomes

Accepted Answer

A)   f1. 
B)   1.2f1. 
C)   1.5f1. 
D)   1.7f1. 
E)   2f1. F) A) and E)
G) A) and B)

Question 15

A musical pitch is played at 60 dB. Another is played that sounds 4 times as loud. The sound intensity level of the second pitch is

Accepted Answer

A)   80 dB.
B)   100 dB.
C)   66 dB.
D)   64 dB.
E)   240 dB.F) A) and E)
G) A) and C)

Question 16

The figure represents a wire of length L, fixed at both ends, vibrating in several harmonics. The 7th harmonic is shown in

Accepted Answer

A)   1) .
B)   2) .
C)   3) .
D)   4) .
E)   5) .F) C) and E)
G) None of the above

Question 17

Two wave trains of the same frequency are traveling in opposite directions down a string. When they meet, these wave trains will not

Accepted Answer

A)   be described by the principle of superposition.
B)   bounce off each other and switch directions.
C)   pass through one another.
D)   continue to carry energy.
E)   remain transverse.F) B) and D)
G) A) and E)

Question 18

The object shown in the figure is

Accepted Answer

A)   traveling from 2 toward 4.
B)   traveling from 3 toward 1.
C)   traveling from 1 toward 3.
D)   traveling from 4 toward 2.
E)   not in motion.F) All of the above
G) C) and D)

Question 19

Both particles and waves transfer energy from one location to another. Which of the following statements is true?

Accepted Answer

A)   Both methods of energy transfer follow the conservation of energy principle.
B)   Energy transfer by particles follows the conservation of energy principle but waves do not.
C)   Energy transfer by waves follows the conservation of energy principle but particles do not.
D)   Whether the transfer of energy by a wave follows the conservation of energy principle depends on the speed of the wave.
E)   Whether the transfer of energy by a particle follows the conservation of energy principle depends on the speed of the particle.F) All of the above
G) A) and E)

Question 20

A police car siren emits a sound at 600 Hz. If an observer moves toward the source at 50 km/hr and hears a siren frequency of 678 Hz, calculate the speed of the police car and whether it is approaching or receding from the observer assume the speed of sound in air is 343 m/s) .

Accepted Answer

A)   99.0 km/hr receding
B)   144 km/hr approaching
C)   99.0 km/hr approaching
D)   144 km/hr receding
E)   Not possible for any reasonable police car speed.F) A) and B)
G) C) and D)

Exam 13: Waves

To double the rate at which energy is transmitted along a string, you could

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Both particles and waves transfer energy from one location to another. Which of the following statements is true?

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A pulse moves in a string toward a free end a ring on a post) as indicated in the sketch. On reflection, the pulse would most nearly be represented by

Correct AnswerverifiedShow Answer

The fundamental frequency of a vibrating string is f1. If the tension in the string is increased by 50% while the linear density is held constant, the fundamental frequency becomes

Correct AnswerverifiedShow Answer

The figure represents a wire of length L, fixed at both ends, vibrating in several harmonics. The 7th harmonic is shown in

Correct AnswerverifiedShow Answer

A musical pitch is played at 60 dB. Another is played that sounds 4 times as loud. The sound intensity level of the second pitch is

Correct AnswerverifiedShow Answer

Which of the following wavefronts results from a supersonic flight?

Correct AnswerverifiedShow Answer

Two wave trains of the same frequency are traveling in opposite directions down a string. When they meet, these wave trains will not

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A string 2.0 m long has a mass of 2.4  10-2 kg. When fixed at both ends, it vibrates with a fundamental frequency of 150 Hz. The speed of a transverse wave in the string is

Correct AnswerverifiedShow Answer

When an organ pipe, which is closed at one end only, vibrates with a frequency that is 3 times its fundamental first harmonic) frequency,

Correct AnswerverifiedShow Answer

If you were to double the speed of a wave on a string while keeping the frequency and amplitude of the wave constant, the rate at which energy is delivered by the wave would

Correct AnswerverifiedShow Answer

The fundamental frequency of a vibrating string is f1. If the tension in the string is quadrupled while the linear density is held constant, the fundamental frequency becomes

Correct AnswerverifiedShow Answer

A sinusoidal wave train is moving along a string. The equation giving the displacement y of a point at coordinate x has the form where the units are SI. The wavelength is

Correct AnswerverifiedShow Answer

The frequency of a car horn is f. What frequency is observed if both the car and the observer are at rest, but a wind is blowing toward the observer?

Correct AnswerverifiedShow Answer

The object shown in the figure is

Correct AnswerverifiedShow Answer

For a tube of length 57.0 cm that is open at both ends, what is the frequency of the fundamental mode? The speed of sound in air is 340 m/s.)

Correct AnswerverifiedShow Answer

The graph shows a wave moving from left to right. If the period of this wave motion is 50 m/s, the wave is moving with a velocity of

Correct AnswerverifiedShow Answer

During the passage of a longitudinal wave, a particle of the medium

Correct AnswerverifiedShow Answer

Car A moves at speed v toward car B, which is at rest. The frequency of car A's horn is observed by car B to be f. What is the frequency of car A's horn as heard by an observer in car B if car A is at rest and car B moves at speed v toward car A assume there is no wind) ?

Correct AnswerverifiedShow Answer

A police car siren emits a sound at 600 Hz. If an observer moves toward the source at 50 km/hr and hears a siren frequency of 678 Hz, calculate the speed of the police car and whether it is approaching or receding from the observer assume the speed of sound in air is 343 m/s) .

Correct AnswerverifiedShow Answer

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The fundamental frequency of a vibrating string is f₁. If the tension in the string is increased by 50% while the linear density is held constant, the fundamental frequency becomes

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A string 2.0 m long has a mass of 2.4  10^-² kg. When fixed at both ends, it vibrates with a fundamental frequency of 150 Hz. The speed of a transverse wave in the string is

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The fundamental frequency of a vibrating string is f₁. If the tension in the string is quadrupled while the linear density is held constant, the fundamental frequency becomes

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