Name: 
 

Unit 4



Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

Which of the following are true for a simple harmonic oscillator?
I.
The speed is a maximum at the equilibrium position.
II.
The speed is a minimum at the equilibrium position.
III.
The acceleration is a maximum at the equilibrium position.
IV.
The acceleration is a minimum at the equilibrium position.
a.
I and III
c.
II and III
b.
I and IV
d.
II and IV
 

 2. 

Which of the following are true for a simple harmonic oscillator?
I.
The restoring force is greatest when the speed of the oscillator is least.
II.
The restoring force is greatest when the speed of the oscillator is greatest.
III.
The acceleration is a maximum at the equilibrium position.
IV.
The acceleration is a minimum at the equilibrium position.
a.
I and III
c.
II and III
b.
I and IV
d.
II and IV
 
 
Water Wave Refraction
In a ripple tank, when the water depth changes, some of the properties of the waves change when they cross from shallow to deep water or from deep to shallow water.

(The diagram is not to scale.)
nar001-1.jpg
 

 3. 

Refer to the diagram Water Wave Refraction to answer this question.
In the lower part of the diagram, the straight wave generator creates 3.50-cm wavelengths that travel at a speed of mc003-1.jpg cm/s toward the line where the water depth changes. When the waves cross this boundary, their wavelength increases to 4.50 cm. The frequency of the waves in this section of the ripple tank is
a.
3.43 Hz
c.
4.41 Hz
b.
3.19 Hz
d.
4.02 Hz
 

 4. 

A 0.620-m pipe of an organ is an open-pipe resonator. If the speed of sound in the hall where the organ is being played is 325 m/s, then the frequency of the note that the pipe creates is
a.
198 Hz
c.
131 Hz
b.
262 Hz
d.
245 Hz
 

 5. 

A mass, P, is attached to a vertical spring and allowed to come to rest at its equilibrium position. The mass is then given a slight pull downward and released so that it moves as a simple harmonic oscillator. Mass P is replaced with mass Q and the same process is repeated. What is the ratio of the frequency of oscillation of the two masses if the mass of P is twice the mass of Q?
a.
mc005-1.jpg
c.
mc005-3.jpg
b.
mc005-2.jpg
d.
mc005-4.jpg
 

 6. 

A mass, P, is attached to a vertical spring and allowed to come to rest at its equilibrium position. The mass is then given a slight pull downward and released so that it moves as a simple harmonic oscillator. Mass P is replaced with mass Q and the same process is repeated. What is the ratio of the period of oscillation of the two masses if the mass of P is four times the mass of Q?
a.
mc006-1.jpg
c.
mc006-3.jpg
b.
mc006-2.jpg
d.
mc006-4.jpg
 

 7. 

A mass, P, is attached to a vertical spring and allowed to come to rest at its equilibrium position. The mass is then given a slight pull downward and released so that it moves as a simple harmonic oscillator. Mass P is replaced with mass Q and the same process is repeated. What is the ratio of the maximum speeds of the two masses during oscillation if the mass of P is four times the mass of Q?
a.
mc007-1.jpg
c.
mc007-3.jpg
b.
mc007-2.jpg
d.
mc007-4.jpg
 

 8. 

A mass is attached to a vertical spring, P, and allowed to come to rest at its equilibrium position. The mass is then given a slight pull downward and released so that it moves as a simple harmonic oscillator. The same procedure is used to start an oscillator, Q, with an equal mass. If the elastic constant of P is three times that of Q, what is the ratio of the frequency of the oscillator using P to that of Q?
a.
mc008-1.jpg
c.
mc008-3.jpg
b.
mc008-2.jpg
d.
mc008-4.jpg
 

 9. 

A 0.250-kg mass, P, is suspended on a spring with an elastic constant of 525 N/m while a 0.750-kg mass, Q, is suspended on a spring with an elastic constant of 1050 N/m. These two spring systems are pulled down slightly and then released to move in simple harmonic motion. What is the ratio of the frequency at which P oscillates compared to the frequency at which Q oscillates?
a.
mc009-1.jpg
c.
mc009-3.jpg
b.
mc009-2.jpg
d.
mc009-4.jpg
 

 10. 

Two pendulums are set up side by side. One pendulum, P, consists of a 0.240-kg mass that is suspended on a string that is 65.0 cm long. The other pendulum, Q, has a 0.360-kg mass that is suspended on a string that is 39.0 cm long. The two masses are pulled aside slightly and released. What is the ratio of the frequency of oscillation of mass P to that of Q?
a.
mc010-1.jpg
c.
mc010-3.jpg
b.
mc010-2.jpg
d.
mc010-4.jpg
 

 11. 

Two harmonic oscillators are created by suspending masses on springs. On one spring, P, a 0.350-kg mass is used while on the other spring, Q, a 0.150-kg mass is used. When the oscillators are set into motion, they have identical periods. What is the spring constant for spring Q if the spring constant of spring P is known to be mc011-1.jpg N/m?
a.
mc011-2.jpg N/m
c.
mc011-4.jpg N/m
b.
mc011-3.jpg N/m
d.
mc011-5.jpg N/m
 
 
Sound Source on a Turntable
An audio frequency source is attached to the outer edge of a turntable. A student is using an oscilloscope to measure the frequency of the sound. As the turntable rotates, the oscilloscope indicates that the frequency from the source increases and decreases.

(The diagram is not to scale.)
nar002-1.jpg
 

 12. 

Refer to the diagram Sound Source on a Turntable to answer this question.
An audio source with a frequency of 256 Hz is attached to the outer edge of a turntable with a radius of 2.50 m and a period of rotation of 0.750 s. If the speed of sound is 335 m/s, what frequency does the oscilloscope register when the source is moving directly toward the student?
a.
273 Hz
c.
263 Hz
b.
292 Hz
d.
282 Hz
 

 13. 

Refer to the diagram Sound Source on a Turntable to answer this question.
An audio source with a frequency of 622 Hz is attached to the outer edge of a turntable with a radius of 5.20 m and a period of rotation of 1.10 s. If the speed of sound is 329 m/s, what frequency does the oscilloscope register when the source is moving directly away from the student?
a.
561 Hz
c.
578 Hz
b.
570 Hz
d.
583 Hz
 

 14. 

Refer to the diagram Sound Source on a Turntable to answer this question.
An audio source with a frequency of 587 Hz is attached to the outer edge of a turntable with a radius of 4.95 m. When the speed of sound is 337 m/s, the oscilloscope registers a frequency of 612 Hz when the source is moving directly toward the student. What is the period of rotation of the turntable?
a.
1.92 s
c.
2.26 s
b.
2.14 s
d.
2.75 s
 

 15. 

Refer to the diagram Sound Source on a Turntable to answer this question.
An mc015-1.jpg audio source is attached to the outer edge of a turntable that is rotating with a period of 0.960 s. When the speed of sound is 341 m/s, the oscilloscope registers a frequency of mc015-2.jpg when the source is moving directly toward the student. What is the radius of the turntable?
a.
3.22 m
c.
2.16 m
b.
3.58 m
d.
2.68 m
 
 
Two Sources in a Ripple Tank
An interference pattern in a ripple tank is created using two in-phase point sources.
nar003-1.jpg
 

 16. 

Refer to the diagram Two Sources in a Ripple Tank to answer this question.
You are studying interference patterns in a ripple tank using two in-phase point sources. You set up the tank, and the first pattern that you generate is the one shown in the diagram. If the sources are 24.0 cm apart, and the frequency of the generator is 2.50 Hz, what is the speed of the waves in the ripple tank?
a.
15.0 cm/s
c.
12.0 cm/s
b.
20.0 cm/s
d.
30.0 cm/s
 

 17. 

Refer to the diagram Two Sources in a Ripple Tank to answer this question.
You are studying interference patterns in a ripple tank using two in-phase point sources. You set up the tank so that the first pattern that you generate is the one shown in the diagram. In this set-up, the sources are 24.0 cm apart and the frequency of the generator is 2.50 Hz. You now increase the frequency of the generator to 3.00 Hz. If you pick a point on a second-order maximum and measure the distance from this point to each of the sources, what is the difference in these measurements?
a.
12.0 cm
c.
11.0 cm
b.
10.0 cm
d.
9.00 cm
 

 18. 

Refer to the diagram Two Sources in a Ripple Tank to answer this question.
You are studying interference patterns in a ripple tank using two in-phase point sources. You set up the tank so that the first pattern that you generate is the one shown in the diagram. In this set-up, the sources are 24.0 cm apart and the frequency of the generator is 2.50 Hz. You now increase the frequency of the generator to 3.60 Hz. If you pick a point on a second-order minimum and measure the distance from this point to each of the sources, what is the difference in these measurements?
a.
7.00 cm
c.
6.50 cm
b.
6.75 m
d.
6.25 cm
 
 
Sand Pendulum
A pendulum bob consists of a small bucket filled with fine sand. As the pendulum oscillates, the sand pours out through a hole in the bottom of the bucket so that it leaves a trail of sand on the surface below. The rope attached to the trolley pulls it to the right at a constant velocity while the pendulum swings across the trolley at right angles to the direction of the trolley’s velocity.

(This diagram is not to scale.)
nar004-1.jpg
 

 19. 

Refer to the diagram Sand Pendulum to answer this question.
When the mc019-1.jpg-long pendulum is set in motion, it swings at right angles to the velocity of the trolley. What is the speed of the trolley if the sand from the pendulum creates a wave pattern on the surface of the trolley with a wavelength of 0.150 m?
a.
mc019-2.jpg m/s
c.
mc019-4.jpg m/s
b.
mc019-3.jpg m/s
d.
mc019-5.jpg m/s
 

 20. 

The 0.450-m-long pendulum is set in motion so that it swings at right angles to the velocity of the trolley. If the speed of the trolley is 0.360 m/s, then the sand from the pendulum creates a wave pattern on the surface of the trolley with a wavelength of 0.485 m. What is the acceleration due to gravity at the location of the pendulum?
a.
9.79 m/s2
c.
9.86 m/s2
b.
9.75 m/s2
d.
9.91 m/s2
 

Numeric Response
 
 
Sound Source on a Turntable
An audio frequency source is attached to the outer edge of a turntable. A student is using an oscilloscope to measure the frequency of the sound. As the turntable rotates, the oscilloscope indicates that the frequency from the source increases and decreases.

(The diagram is not to scale.)
nar002-1.jpg
 

 21. 

Refer to the diagram Sound Source on a Turntable to answer this question.
The source on the turntable is set to generate sound at a frequency of 584 Hz. The turntable is set in motion so that its period of rotation is 1.75 s. The turntable has a radius of 6.75 m and the speed of sound in air is 335 m/s. Given this information, the difference between the highest and lowest frequencies that the oscilloscope would detect is ______ Hz. (Record your three-digit answer on the answer sheet.)

 

 22. 

Refer to the diagram Sound Source on a Turntable to answer this question.
When the nr022-1.jpg sound source is moving directly away from the student, the oscilloscope registers a frequency of 508 Hz. If the speed of sound is 338 m/s and the turntable has a 2.95-m radius, then the centripetal acceleration of the sound source is ______ m/s2. (Record your three-digit answer on the answer sheet.)

 

 23. 

Refer to the diagram Sound Source on a Turntable to answer this question.
As the turntable rotates, the oscilloscope indicates that the frequency varies between a high of nr023-1.jpg and a low of nr023-2.jpg. If the speed of sound in air is 342 m/s and the turntable has a radius of nr023-3.jpg, then the centripetal acceleration of the sound source as it travels along the circumference of the circle is ______ m/s2. (Record your three-digit answer on the answer sheet.)

 

 24. 

Refer to the diagram Sound Source on a Turntable to answer this question.
As the turntable rotates, the oscilloscope indicates that the frequency varies between a high of 365 Hz and a low of nr024-1.jpg. If the speed of sound in air is 342 m/s and the turntable has a radius of nr024-2.jpg, then the period of rotation for the turntable is ______ s. (Record your three-digit answer on the answer sheet.)

 
 
Water Wave Refraction
In a ripple tank, when the water depth changes, some of the properties of the waves change when they cross from shallow to deep water or from deep to shallow water.

(The diagram is not to scale.)
nar001-1.jpg
 

 25. 

Refer to the diagram Water Wave Refraction to answer this question.
The 1.85-cm waves travel from the generator and cross the boundary where the water depth changes. In the lower part of the diagram, the speed of the waves is nr025-1.jpg cm/s. If the wavelength of the waves in the upper part of the diagram is 2.86 cm, then the frequency of the waves in the upper region of the ripple tank is ______ nr025-2.jpg. (Record your three-digit answer on the answer sheet.)

 

Essay
 

 26. 

The diagram shows a section of the sound wave trains created by two small speakers set up beside each other. [Note: The waves shown are transverse wave representations of the longitudinal sound waves actually created by the speakers.]

As the waves pass the vertical line P, both waves have troughs at that point so that they are in phase. Because they have different wavelengths, their phases shift so that they are not in phase again until line Q, at which point they both have crests.

es026-1.jpg
(a)
Speaker A is generating a wave with a frequency of 448 Hz. If the speed of sound is
336 m/s, what is the frequency of sound created by speaker B?
(b)
At what frequency do the two waves shift out of and back into phase?
 



 
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