Two people are talking at a distance of 3.0 m from where you are,and you measure the sound intensity as 1.1 × 10-7 W/m2.Another student is 4.0 m away from the talkers.Calculate a reasonable estimate for the sound intensity that the other student measures.

A) 6.2 × 10-8 W/m2 B) 1.5 × 10-7 W/m2 C) 8.3 × 10-8 W/m2 D) 7.8 × 10-7 W/m2 E) 2.5 × 10-8 W/m2 A) 6.2 × 10-8 W/m2 B) 1.5 × 10-7 W/m2 C) 8.3 × 10-8 W/m2 D) 7.8 × 10-7 W/m2 E) 2.5 × 10-8 W/m2

Exam 21: Mechanical Waves

A person stands between two speakers driven by the same source.Each speaker produces a tone with a frequency of 200 Hz on a day when the speed of sound is 330 m/s.The person is 1.65 m from one speaker and 4.95 m from the other.What type of interference does the person perceive?

(Multiple Choice)

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Question 41

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 $1340 \mathrm {~Hz}$ You are relieved that he is in pursuit of a different driver when he continues past you,but now you perceive the frequency as $1300 \mathrm {~Hz} .$ What is the speed of the police car? The speed of sound in air is $343 \mathrm {~m} / \mathrm { s } .$

(Multiple Choice)

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Question 42

By how many decibels does the intensity level of a sound decrease when you triple your distance from a source of sound?

(Multiple Choice)

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Question 43

As shown in the figure,a man is traveling on a bicycle along a straight road that runs parallel to and right next to some railroad tracks.While moving at 10 m/s,he hears the whistle of a train that is behind him,as shown in the figure.The frequency emitted by the train's whistle is $820 \mathrm {~Hz}$ but the frequency the man hears is $774 \mathrm {~Hz}$ The speed of sound is 340 m/s. (a)What frequency is heard by a stationary observer located between the train and the bicycle? (b)What is the speed of the train,and is the train traveling away from or toward the bicycle? $As shown in the figure,a man is traveling on a bicycle along a straight road that runs parallel to and right next to some railroad tracks.While moving at 10 m/s,he hears the whistle of a train that is behind him,as shown in the figure.The frequency emitted by the train's whistle is 820 \mathrm {~Hz} but the frequency the man hears is 774 \mathrm {~Hz} The speed of sound is 340 m/s. (a)What frequency is heard by a stationary observer located between the train and the bicycle? (b)What is the speed of the train,and is the train traveling away from or toward the bicycle?$

(Short Answer)

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Question 44

If a guitar string has a fundamental frequency of 500 Hz,which one of the following frequencies can set the string into resonant vibration?

(Multiple Choice)

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Question 45

Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are separated by a distance of 8.00 m.A person is standing 12.0 m away from the wall,equidistant from the loudspeakers.When the person moves 3.00 m parallel to the wall,she hears no sound (experiences destructive interference)for the second time.What is the frequency of the sound? The speed of sound in air is 343 m/s.

(Multiple Choice)

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Question 46

A crane lifts a 2500-kg beam at a steady rate of 15 cm/s using a steel cable whose mass per unit length is 0.65 kg/m.What is the speed of transverse waves on this cable?

(Multiple Choice)

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Question 47

Crests of an ocean wave pass a pier every $10.0 \mathrm {~s}$ If the waves are moving at $5.6 \mathrm {~m} / \mathrm { s }$ what is the wavelength of the ocean waves?

(Multiple Choice)

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Question 48

The lowest tone to resonate in a pipe of length L that is closed at one end but open at the other end is 200 Hz.Which one of the following frequencies will not resonate in that pipe?

(Multiple Choice)

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Question 49

A 2.0-g string that is 0.67 m long is under tension.The string vibrates at 700 Hz tone in its third harmonic,and this vibration causes a sound wave.What is the wavelength of the sound? The speed of sound in air is 344 m/s.

(Multiple Choice)

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Question 50

What is the frequency of the wave shown in the figure?

(Multiple Choice)

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Question 51

A whistle produces sound of frequency of 1.00 kHz.If a listener moves with a speed of 30 m/s away from the whistle,what frequency does this person hear if the sound speed is 340 m/s?

(Multiple Choice)

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Question 52

Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are separated by a distance of 5.00 m.A person is standing 12.0 m away from the wall,equidistant from the loudspeakers.When the person moves 1.00 m parallel to the wall,she hears no sound (experiences destructive interference)for the first time.What is the frequency of the sound? The speed of sound in air is 343 m/s.

(Multiple Choice)

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(80)

Question 53

Two people are talking at a distance of 3.0 m from where you are,and you measure the sound intensity as 1.1 × 10^-7 W/m².Another student is 4.0 m away from the talkers.Calculate a reasonable estimate for the sound intensity that the other student measures.

(Multiple Choice)

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Question 54

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?

(Multiple Choice)

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Question 55

The intensity of the waves from a point source at a distance d from the source is I.What is the intensity at a distance 2d from the source?

(Multiple Choice)

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Question 56

A bat emits a sound at a frequency of 39.0 kHz as it approaches a wall.The bat detects beats with a frequency of 827 Hz between the sound it emits and the echo bouncing from the wall.What is the speed of the bat if the speed of sound in air is 343 m/s?

(Multiple Choice)

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Question 57

If the intensity level by 15 identical engines in a garage is 100 dB,what is the intensity level generated by each one of these engines?

(Multiple Choice)

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Question 58

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.

(Multiple Choice)

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Question 59

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?

(Multiple Choice)

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Question 60

Showing 41 - 60 of 155

Exam 21: Mechanical Waves

A person stands between two speakers driven by the same source.Each speaker produces a tone with a frequency of 200 Hz on a day when the speed of sound is 330 m/s.The person is 1.65 m from one speaker and 4.95 m from the other.What type of interference does the person perceive?

By how many decibels does the intensity level of a sound decrease when you triple your distance from a source of sound?

If a guitar string has a fundamental frequency of 500 Hz,which one of the following frequencies can set the string into resonant vibration?

A crane lifts a 2500-kg beam at a steady rate of 15 cm/s using a steel cable whose mass per unit length is 0.65 kg/m.What is the speed of transverse waves on this cable?

Crests of an ocean wave pass a pier every 10.0 s10.0 \mathrm {~s}10.0 s If the waves are moving at 5.6 m/s5.6 \mathrm {~m} / \mathrm { s }5.6 m/s what is the wavelength of the ocean waves?

The lowest tone to resonate in a pipe of length L that is closed at one end but open at the other end is 200 Hz.Which one of the following frequencies will not resonate in that pipe?

A 2.0-g string that is 0.67 m long is under tension.The string vibrates at 700 Hz tone in its third harmonic,and this vibration causes a sound wave.What is the wavelength of the sound? The speed of sound in air is 344 m/s.

What is the frequency of the wave shown in the figure?

A whistle produces sound of frequency of 1.00 kHz.If a listener moves with a speed of 30 m/s away from the whistle,what frequency does this person hear if the sound speed is 340 m/s?

Two people are talking at a distance of 3.0 m from where you are,and you measure the sound intensity as 1.1 × 10-7 W/m2.Another student is 4.0 m away from the talkers.Calculate a reasonable estimate for the sound intensity that the other student measures.

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?

The intensity of the waves from a point source at a distance d from the source is I.What is the intensity at a distance 2d from the source?

A bat emits a sound at a frequency of 39.0 kHz as it approaches a wall.The bat detects beats with a frequency of 827 Hz between the sound it emits and the echo bouncing from the wall.What is the speed of the bat if the speed of sound in air is 343 m/s?

If the intensity level by 15 identical engines in a garage is 100 dB,what is the intensity level generated by each one of these engines?

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?

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Crests of an ocean wave pass a pier every $10.0 \mathrm {~s}$ If the waves are moving at $5.6 \mathrm {~m} / \mathrm { s }$ what is the wavelength of the ocean waves?

Two people are talking at a distance of 3.0 m from where you are,and you measure the sound intensity as 1.1 × 10^-7 W/m².Another student is 4.0 m away from the talkers.Calculate a reasonable estimate for the sound intensity that the other student measures.