Question 1

The density of aluminum is 2700 kg/m3.If transverse waves travel at  
In an aluminum wire of diameter  
What is the tension on the wire?

Accepted Answer

A) 65 N 
B) 39 N 
C) 52 N 
D) 78 N 
A) 65 N 
B) 39 N 
C) 52 N 
D) 78 N

Question 2

If the frequency of a violin string is to be increased by 20%,what change in tension must be applied?

Accepted Answer

A) 44% 
B) 20% 
C) 4.5% 
D) 10% 
A) 44% 
B) 20% 
C) 4.5% 
D) 10%

Question 3

An pipe of length L that is open at both ends is resonating at its fundamental frequency.Which statement about the sound is correct?

Accepted Answer

A) The wavelength is 2L and there is a displacement node at the pipe's midpoint. 
B) The wavelength is 2L and there is a displacement antinode at the pipe's midpoint. 
C) The wavelength is L and there is a displacement node at the pipe's midpoint. 
D) The wavelength is L and there is a displacement antinode at the pipe's midpoint. 
A) The wavelength is 2L and there is a displacement node at the pipe's midpoint. 
B) The wavelength is 2L and there is a displacement antinode at the pipe's midpoint. 
C) The wavelength is L and there is a displacement node at the pipe's midpoint. 
D) The wavelength is L and there is a displacement antinode at the pipe's midpoint.

Question 4

You are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind at constant speed and you perceive the frequency as 1310 Hz.You are relieved that he is in pursuit of a different driver when he continues past you,but now you perceive the frequency as 1240 Hz.What is the frequency of the siren in the police car? The speed of sound in air is 343 m/s.

Accepted Answer

A) 1300 Hz 
B) 1320 Hz 
C) 1270 Hz 
D) 1360 Hz 
E) 1370 Hz 
A) 1300 Hz 
B) 1320 Hz 
C) 1270 Hz 
D) 1360 Hz 
E) 1370 Hz

Question 5

Two in-phase loudspeakers are placed along a wall and are separated by a distance of 4.00 m.They emit sound with a frequency of 514 Hz.A person is standing away from the wall,in front of one of the loudspeakers.What is the closest distance from the wall the person can stand and hear destructive interference? The speed of sound in air is 343 m/s.

Accepted Answer

A) 0.34 m 
B) 0.37 m 
C) 0.73 m 
D) 1.2 m 
E) 1.6 m 
A) 0.34 m 
B) 0.37 m 
C) 0.73 m 
D) 1.2 m 
E) 1.6 m

Question 6

A pipe of length L that is closed at one end and open at the other end is resonating at its fundamental frequency.Which statement about the sound is correct?

Accepted Answer

A) The wavelength is 4L and there is a displacement node at the pipe's open end. 
B) The wavelength is 4L and there is a displacement antinode at the pipe's open end. 
C) The wavelength is L and there is a displacement node at the pipe's open end. 
D) The wavelength is L and there is a displacement antinode at the pipe's open end. 
A) The wavelength is 4L and there is a displacement node at the pipe's open end. 
B) The wavelength is 4L and there is a displacement antinode at the pipe's open end. 
C) The wavelength is L and there is a displacement node at the pipe's open end. 
D) The wavelength is L and there is a displacement antinode at the pipe's open end.

Question 7

In many cartoon shows,a character runs off a cliff,realizes his predicament,and lets out a scream.He continues to scream as he falls.If the physical situation is portrayed correctly,from the vantage point of an observer at the top of the cliff leaning over the edge,the pitch of the scream as he falls should be

Accepted Answer

A) higher than the original pitch and constant. 
B) higher than the original pitch and increasing as he falls. 
C) lower than the original pitch and constant. 
D) lower than the original pitch and decreasing as he falls. 
E) It is impossible to predict. 
A) higher than the original pitch and constant. 
B) higher than the original pitch and increasing as he falls. 
C) lower than the original pitch and constant. 
D) lower than the original pitch and decreasing as he falls. 
E) It is impossible to predict.

Question 8

What is the ratio of the intensities of two sounds with intensity levels of 70 dB and 40 dB?

Accepted Answer

A) 10:1 
B) 100:1 
C) 1000:1 
D) 10,000:1 
A) 10:1 
B) 100:1 
C) 1000:1 
D) 10,000:1

Question 9

Two in-phase loudspeakers are placed along a wall and are separated by a distance of 4.00 m.They emit sound with a frequency of 514 Hz.A person is standing away from the wall,in front of one of the loudspeakers.What is the closest nonzero distance from the wall the person can stand and hear constructive interference? The speed of sound in air is 343 m/s.

Accepted Answer

A) 0.34 m 
B) 0.73 m 
C) 1.2 m 
D) 1.6 m 
A) 0.34 m 
B) 0.73 m 
C) 1.2 m 
D) 1.6 m

Question 10

What is the frequency does a stationary observer hear when a train approaches her with a speed of 30 m/s.The frequency of the train horn is 0.600 kHz and the speed of sound is 340 m/s.

Accepted Answer

A) 551 Hz 
B) 600 Hz 
C) 653 Hz 
D) 658 Hz 
A) 551 Hz 
B) 600 Hz 
C) 653 Hz 
D) 658 Hz

Question 11

A guitar-like stringed instrument has a string that is 16 cm long.It sounds the musical note A (440 Hz)when played without fingering.By what distance should you shorten it to play the note C (523 Hz)?

Accepted Answer

A) 2.5 cm 
B) 1.7 cm 
C) 3.4 cm 
D) 4.2 cm 
A) 2.5 cm 
B) 1.7 cm 
C) 3.4 cm 
D) 4.2 cm

Question 12

The lowest tone to resonate in pipe of length L that is open at both ends is 200 Hz.Which one of the following frequencies will not resonate in the same pipe?

Accepted Answer

A) 200 Hz 
B) 400 Hz 
C) 600 Hz 
D) 800 Hz 
E) 900 Hz 
A) 200 Hz 
B) 400 Hz 
C) 600 Hz 
D) 800 Hz 
E) 900 Hz

Question 13

A 1.1-kg uniform bar of metal is 0.40 m long and has a diameter of 2.0 cm.When someone bangs one end of this bar,a 1.5 MHz shock wave is travels along the length of the bar and reaches the other end in 0.12 ms.What is the wavelength of the shock wave in the metal?

Accepted Answer

A) 2.2 mm 
B) 2.6 mm 
C) 3.0 mm 
D) 3.4 mm 
E) 3.8 mm 
A) 2.2 mm 
B) 2.6 mm 
C) 3.0 mm 
D) 3.4 mm 
E) 3.8 mm

Question 14

Consider a pipe of length L that is open at both ends.What are the wavelengths of the three lowest-pitch tones produced by this pipe?

Accepted Answer

A) 4L,2L,L 
B) 2L,L,L/2 
C) 2L,L,2L/3 
D) 4L,4L/3,4L/5 
A) 4L,2L,L 
B) 2L,L,L/2 
C) 2L,L,2L/3 
D) 4L,4L/3,4L/5

Question 15

A certain factory whistle can be heard up to a distance of 2.5 km.Assuming that the acoustic output of the whistle is uniform in all directions,how much acoustic power is emitted by the whistle? The threshold of human hearing is 1.0 × 10-12 W/m2.

Accepted Answer

A) 0.079 mW 
B) 0.026 mW 
C) 0.26 mW 
D) 0.79 mW 
E) 2.6 mW 
A) 0.079 mW 
B) 0.026 mW 
C) 0.26 mW 
D) 0.79 mW 
E) 2.6 mW

Question 16

A sound of 40 decibels is

Accepted Answer

A) twice as intense as a sound of 20 decibels. 
B) four times as intense as a sound of 20 decibels. 
C) 10 times as intense as a sound of 20 decibels. 
D) 100 times as intense as a sound of 20 decibels. 
E) 1000 times as intense as a sound of 20 decibels. 
A) twice as intense as a sound of 20 decibels. 
B) four times as intense as a sound of 20 decibels. 
C) 10 times as intense as a sound of 20 decibels. 
D) 100 times as intense as a sound of 20 decibels. 
E) 1000 times as intense as a sound of 20 decibels.

Question 17

If a wave has a speed of 362 m/s and a period of 4.17 ms,what is its wavelength?

Accepted Answer

A) 1510 m 
B) 1.51 m 
C) 86.8 m 
D) 86,800 m 
E) 0.0115 m 
A) 1510 m 
B) 1.51 m 
C) 86.8 m 
D) 86,800 m 
E) 0.0115 m

Question 18

A 2.31-kg rope is stretched between supports that are 10.4 m apart,and has a tension in it of 49.2 N.If one end of the rope is slightly tweaked,how long will it take for the resulting disturbance to reach the other end?

Accepted Answer

A) 0.699 s 
B) 0.720 s 
C) 0.664 s 
D) 0.615 s 
A) 0.699 s 
B) 0.720 s 
C) 0.664 s 
D) 0.615 s

Question 19

A police car has an 800-Hz siren.It is traveling at 35.0 m/s on a day when the speed of sound through air is 340 m/s.The car approaches and passes an observer who is standing along the roadside.What change of frequency does the observer hear?

Accepted Answer

A) 0 Hz 
B) 82 HZ 
C) 166 Hz 
D) 249 Hz 
A) 0 Hz 
B) 82 HZ 
C) 166 Hz 
D) 249 Hz

Question 20

An organ pipe of length L that is open at one end resonates in its third harmonic with a wavelength of 2L/3.Is the other end of the pipe closed or open?

Accepted Answer

A) closed 
B) open 
C) We cannot tell from the information provided. 
A) closed 
B) open 
C) We cannot tell from the information provided.

Exam 14: Waves and Sound

The density of aluminum is 2700 kg/m3.If transverse waves travel at In an aluminum wire of diameter What is the tension on the wire?

If the frequency of a violin string is to be increased by 20%,what change in tension must be applied?

An pipe of length L that is open at both ends is resonating at its fundamental frequency.Which statement about the sound is correct?

A pipe of length L that is closed at one end and open at the other end is resonating at its fundamental frequency.Which statement about the sound is correct?

What is the ratio of the intensities of two sounds with intensity levels of 70 dB and 40 dB?

What is the frequency does a stationary observer hear when a train approaches her with a speed of 30 m/s.The frequency of the train horn is 0.600 kHz and the speed of sound is 340 m/s.

A guitar-like stringed instrument has a string that is 16 cm long.It sounds the musical note A (440 Hz)when played without fingering.By what distance should you shorten it to play the note C (523 Hz)?

The lowest tone to resonate in pipe of length L that is open at both ends is 200 Hz.Which one of the following frequencies will not resonate in the same pipe?

A 1.1-kg uniform bar of metal is 0.40 m long and has a diameter of 2.0 cm.When someone bangs one end of this bar,a 1.5 MHz shock wave is travels along the length of the bar and reaches the other end in 0.12 ms.What is the wavelength of the shock wave in the metal?

Consider a pipe of length L that is open at both ends.What are the wavelengths of the three lowest-pitch tones produced by this pipe?

A certain factory whistle can be heard up to a distance of 2.5 km.Assuming that the acoustic output of the whistle is uniform in all directions,how much acoustic power is emitted by the whistle? The threshold of human hearing is 1.0 × 10-12 W/m2.

A sound of 40 decibels is

If a wave has a speed of 362 m/s and a period of 4.17 ms,what is its wavelength?

A 2.31-kg rope is stretched between supports that are 10.4 m apart,and has a tension in it of 49.2 N.If one end of the rope is slightly tweaked,how long will it take for the resulting disturbance to reach the other end?

A police car has an 800-Hz siren.It is traveling at 35.0 m/s on a day when the speed of sound through air is 340 m/s.The car approaches and passes an observer who is standing along the roadside.What change of frequency does the observer hear?

An organ pipe of length L that is open at one end resonates in its third harmonic with a wavelength of 2L/3.Is the other end of the pipe closed or open?

Introduction to Physics

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Vectors in Physics

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Newtons Laws of Motion

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Linear Momentum and Collisions

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Magnetism

Magnetic Flux and Faradays Law of Induction

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The density of aluminum is 2700 kg/m³.If transverse waves travel at In an aluminum wire of diameter What is the tension on the wire?

A certain factory whistle can be heard up to a distance of 2.5 km.Assuming that the acoustic output of the whistle is uniform in all directions,how much acoustic power is emitted by the whistle? The threshold of human hearing is 1.0 × 10^-12 W/m².