Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 1

Student:Mr. KhalilianAP PhysicsDue Date:

MECHANICAL WAVES AND SOUND UNIT PACKETINCLUDES GUIDES FOR NOTES, HW, AND CW

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 2

Student:Mr. KhalilianAP PhysicsDue Date: UNIT 8 AGENDA

____ Day 1: Introduction to Mechanical Waves and Sound Pre-HW: Read the Mechanical Waves Lab Background and complete the pre-lab questions (p. 4-6) Mechanical Wave Intro Lab (p. 7-8) HW: Read text 15.1-15.2 and take notes using guide (p. 3)

____ Day 2: The Basics of Mechanical Waves and Sound Read Text 15.3 – 16.2 and take notes using note guide (p. 3); when finished, check your notes Begin Behavior of 1-D Waves (p. 9-11) HW: Finish reading if you did not finish in class (all notes and Behavior of 1-D waves due Monday)

__3/13__ Day 3: The Basics of Mechanical Waves and Sound Finish Behavior of 1-D Waves (p. 9-11) Read Text 16.3 – 16.7 and take notes using the note guide (p. 3); when finished, check your notes HW: All notes and Behavior of 1-D waves due Monday

___3/16_ Day 4: Standing Waves Four in Five, p. 24 Standing Waves on Strings (p. 12) and in Pipes (p. 13-14) HW: Multiple Choice #1-3, on a separate sheet of paper with explanations (p. 20)

__3/17__ Day 5: Standing Waves Practice Standing Waves Practice Problems (p. 15-16) HW: Finish Standing Waves Practice Problems; Multiple Choice #4-6, on a separate sheet of paper

with explanations (p. 20)

__3/18__ Day 6: Practical Applications of Waves Practical Applications of Waves (p. 17) Multiple Choice #7-12 (p. 20-21) HW: 1995B6 (p. 22)

__3/19__ Day 7: General Waves Practice/ Begin Musical Instruments Four in Five, p. 25 1998B5 (p. 23) HW: Musical Instrument

__3/20__ Day 8: Musical Instruments Work HW: Create Musical Instrument/Practice Performance

__3/23__ Day 9: Musical Instruments Performances

Recommended Book Problems for the Unit: p. 495: 1, 3, 5; p. 496: 9, 11, 13, 15, 23; p. 525: 1, 5, 7, 9; p. 526: 11, 13, 23

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 3

Student:Mr. KhalilianAP PhysicsDue Date: NOTES OUTLINE Notes for this unit should be taken in your notebook. You may use either Cornell or Outline style, but only Outline is presented below. However, instead of giving you where to stop and summarize, you have just been given the headers to set up your notes.Hint #1: Focus on the vocabulary. Know what each term means, and, if it has a symbol, what it stands for.Hint #2: The ONLY equation you will really need is the Fundamental Relationship for Sinusoidal Waves.I. 15.1: The Wave Model

a. Intro Paragraphb. Mechanical Wavesc. Electromagnetic and Matter Waves SKIPd. Transverse and Longitudinal Waves

II. 15.2: Traveling Wavesa. Waves on a Stringb. Sound Wavesc. Wave Speed is a Property of the Medium

III. 15.3: Graphical and Mathematical Descriptions of Wavesa. Snapshot and History Graphsb. Sinusoidal Wavesc. The Fundamental Relationship for Sinusoidal Waves

IV. 15.4: Sound and Light Wavesa. Sound Wavesb. Light and Other Electromagnetic Waves SKIP

V. 15.5: Energy and Intensity SKIPVI. 15.6: Loudness of Sound

a. Introb. The Decibel Scale

VII. 15.7: The Doppler Effect and Shock Wavesa. Sound Waves from a Moving Sourceb. A Stationary Source and a Moving Observerc. The Doppler Effect for Light Wavesd. Frequency Shirt on Reflection from a Moving Object SKIPe. Shock Waves

VIII.16.1: The Principle of Superpositiona. Introb. Constructive and Destructive Interference

IX. 16.2: Standing Wavesa. Superposition Creates a Standing Waveb. Nodes and Antinodes

X. 16.3: Standing Waves on a Stringa. Reflectionsb. Creating a Standing Wavec. The Fundamental and the Higher Harmonicsd. Stringed Musical Instrumentse. Standing Electromagnetic Waves SKIP

XI. 16.4: Standing Sound Wavesa. Introb. Wind Instruments

XII. 16.5: Speech and Hearing SKIPXIII. 16.6: The Interference of Waves from Two Sources Read but no notes necessaryXIV. 16.7: Beats

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 4

Student:Mr. KhalilianAP PhysicsDue Date:

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 5

Student:Mr. KhalilianAP PhysicsDue Date:

Pre-Lab Questions: 1. Compare and contrast transverse and longitudinal waves. __________________________________________________________________________________________

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Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 6

Student:Mr. KhalilianAP PhysicsDue Date: 2. A fishing bobber floating on the water bobs up and down and back to a point of equilibrium once every 1.2 seconds.a. Explain what type of wave is causing the bobber to move up and down.

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b. What is the frequency of the water wave?

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c. What is the period of the wave?

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3. Refer to the diagram below in which the vertical distance from the highest point on the wave to the lowest point represents 0.1 m, and the horizontal distance from one letter to the next is 0.05 m.

a. What is the amplitude of the wave?

b. Describe the wavelength in terms of letter intervals. What distance does this represent (in meters)?

c. If the wave travels from point A to point G in 4.5 seconds, what is the speed of the wave?

d. Determine the period of the wave described above.

e. Calculate the frequency of the wave.

Safety Notes

Take care not to suddenly release a stretched Slinky. Always hold a stretched Slinky carefully. Otherwise, the spring may snap back rapidly, which may cause personal injury or damage to the Slinky. Do not extend the Slinky more than 4 meters.

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 7

Student:Mr. KhalilianAP PhysicsDue Date: MECHANICAL WAVES LABNote: Most of your evidence today will be observational. Feel free to sketch pictures or describe with words. Use the background reading or textbook reading to find the reasoning.1. Claim: For a transverse wave, the wave carries the material from one end to the other as it moves. (Hint: tie

a string to a portion of the slinky and watch what happens to the string.) a. Valid or Invalid? _____________________b. Evidence:

c. Reasoning: __________________________________________________________________________________________

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2. Claim: For a transverse wave, the more energy put into the wave, the faster it will travel.

a. Valid or Invalid? _____________________b. Evidence:

c. Reasoning: __________________________________________________________________________________________

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3. Claim: For a transverse wave, the wave stops when it reaches the end of the Slinky.

a. Valid or Invalid? _____________________b. Evidence:

c. Reasoning: __________________________________________________________________________________________

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Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 8

Student:Mr. KhalilianAP PhysicsDue Date: 4. Claim: For a longitudinal wave, the wave carries the material from one end to the other as it moves. (Hint:

tie a string to a portion of the slinky and watch what happens to the string.) a. Valid or Invalid? _____________________b. Evidence:

c. Reasoning: __________________________________________________________________________________________

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5. Claim: For a longitudinal wave, the more energy put into the wave, the faster it will travel.

a. Valid or Invalid? _____________________b. Evidence:

c. Reasoning: __________________________________________________________________________________________

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6. Claim: For a longitudinal wave, the wave stops when it reaches the end of the Slinky.

a. Valid or Invalid? _____________________b. Evidence:

c. Reasoning: __________________________________________________________________________________________

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7. How can you create a standing wave with an antinode?

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 9

Student:Mr. KhalilianAP PhysicsDue Date: BEHAVIOR OF 1-D WAVES

A long rope rests on the floor. Its far end is firmly attached to a wall. The stick figure at the left gives the rope a brief, horizontal shake, sending a disturbance, or pulse, along the rope toward the wall. In the diagram, points A, B, C, D, and E are equidistant. Point E is at the wall.

All waves have a source that initiates the disturbance. Except for electromagnetic waves (like radio, microwaves, light etc.), waves have a medium through which they travel. All waves transmit energy away from the source. 1. What is the source of the wave in the rope?

2. What is the medium of transmission of the pulse?

3. Is this pulse a transverse or longitudinal wave? Why?

4. The speed at which the wave travels on the rope is 2.0 m/s. The distance between A and B, B and C, C and D, and D and E is 2.0 meters. Let’s call time zero when the pulse is centered on A (see diagram below).

a. In 2.0 seconds after the picture shown above, where will the pulse be centered?

b. Draw the appearance of the pulse at that moment.

c. Where will the pulse be centered 3.0 seconds after the picture shown above?

d. When pulses strike solid barriers, they reflect on the opposite side of the medium. Where will the pulse be centered 7.0 seconds from the picture above? Draw the appearance of the rope at that moment.

e. Repeat question 4d if the rope is not fixed to the wall. When pulses reflect from a “free” end, they return on the same side of the medium.

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 10

Student:Mr. KhalilianAP PhysicsDue Date: 5. Next we have two new pictures of a wave traveling from medium W to medium Z. (Square waves are

drawn for simplicity.) The energy of the original wave is partly transmitted to Z and partly reflected back into W. See Figures C and D below.

a. There are two ways we can recognize that waves travel faster in Z than in W. Using Figures C and

D, explain what they are.

b. There is one feature in these diagrams that suggests that medium Z is not nearly as dense as medium W. Explain.

c. Why is the reflected pulse in medium W smaller than the original pulse in medium W?

6. The pictures below show two pulses on the same medium moving toward each other. Draw the appearance of the medium at the instant when the centers of the pulses overlap at point X. The first question has been completed for you.

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 11

Student:Mr. KhalilianAP PhysicsDue Date:

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 12

Student:Mr. KhalilianAP PhysicsDue Date: STANDING WAVES ON STRINGS

You have a string, and both ends are fixed. String has length L, and the speed of waves is v=√ FT

m / L.

Points of NO oscillation are called = _________________________Points of MAXIMUM oscillation are called = _________________________

General Equations

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 13

Student:Mr. KhalilianAP PhysicsDue Date: STANDING WAVES IN PIPES (open pipes)

General Equations

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Student:Mr. KhalilianAP PhysicsDue Date: STANDING WAVES IN PIPES (closed pipes)

General Equations

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 15

Student:Mr. KhalilianAP PhysicsDue Date: STANDING WAVES PRACTICE PROBLEMS 1. The tension in a particular string is 5.0 N, and the density (m/L) of that string is 0.0004 kg/m. What is the

speed of waves on that string?

2. You are given a piece of string of density 0.00036 kg/m. You need waves which travel at a speed of 100 m/s on the string. What should the tension in the string be?

3. A standing wave with a fundamental frequency 125 Hz is set up in a string which is 2.5 m long. a. What is the speed of the waves on this string?

b. What is the frequency of the…i. first harmonic?

ii. second harmonic?

iii. third harmonic?

4. What are the frequencies of the first four harmonics in a pipe of length 75 cm if the pipe is:a. open at both ends? Assume the temperature of air is 20°C.

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 16

Student:Mr. KhalilianAP PhysicsDue Date:

b. closed at one end? Assume the temperature of air is 20°C.

5. An open organ pipe is designed to produce a frequency of 440 Hz at a temperature of 20°C. By what percent is the frequency increased or decreased if the temperature of the air is 15°C?

6. A 2.0 m long air column is open at both ends. The frequency of a certain harmonic is 410 Hz, and the frequency of the next higher harmonic is 492 Hz. Determine the speed of sound of air in the column.

7. A flute is designed so that it plays a frequency of 261.6 Hz, middle C, when all the holes are covered and the temperature is 20°C.

a. Consider the flute to be open at both ends and find its length, assuming that the middle C frequency is the fundamental.

b. A second player, nearby in a colder room, also attempts to play middle C on an identical flute. A beat frequency of 3 beats per second is heard. What is the temperature of the room?

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 17

Student:Mr. KhalilianAP PhysicsDue Date: PRACTICAL APPLICATIONS OF WAVES1. When a person inhales helium, why does his or her voice mimic a cartoon?

2. How can you tell if an ambulance is moving toward you or away from you?

3. If guitar strings are all the same length, why do they make different notes?

4. How do pianos create different notes?

5. How do flutes create different notes?

6. How can we tell that the universe is expanding?

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 18

Student:Mr. KhalilianAP PhysicsDue Date:

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 19

Student:Mr. KhalilianAP PhysicsDue Date:

Due Date:March 23rd, 2015 in class

Student Name:Course Name: AP PhysicsPeriod: 3 Teacher Name: Ms. Elbein

Assignment Title: Build a(n) (Insert name of Musical Instrument Here)Assignment Summary:

Your job is to use what you have learned about waves, specifically sound waves and standing waves, to build a musical instrument. Your instrument may be a stringed instrument or a wind instrument. Your instrument must play a full octave scale and be in tune. Mr. Redick will (hopefully) come to your performance to hear if your instrument is in tune.

There will be no write-up, only your performance. You must play an entire octave and then perform one short song. You may use a note sheet for your performance.

You may choose your own performance song. It must have a tune though. Please, no Sondheim.

Materials You must purchase your own materials. However, you should not be spending a lot of money on this. Decide what you want. If you aren’t sure where to find something, let Ms. Elbein know. If cost is an issue, let Ms. Elbein know (or let your advisor know to let Ms. Elbein know).

Some recommended materials are: pipes (of any variety), straws, string, wooden boards, etc. Be creative. What can you make a pipe out of?

Procedure and Helpful Hints:

1. Figure out what an octave is and what frequencies each of your notes should be at.2. Figure out what length your pipes/strings/whatever need to be. Or where your

holes should be cut.3. Make the instrument.4. Tune the instrument.5. Find a song that is one-octave only and less than a minute long. Prepare yourself.

Practice.Rubric

______ Instrument played full octave (20 pts)

______ Instrument was in tune (20 pts)

______ Scholar played full song (10 pts)

______ Scholar demonstrates knowledge of why sounds were created and is able to use vocabulary comfortably and correctly (50 pts)

Student did not submit the assignment.

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 20

Student:Mr. KhalilianAP PhysicsDue Date: MECHANICAL WAVES AND SOUND PRACTICE AND REVIEW

1. A string is firmly attached at both ends. When a frequency of 60 Hz is applied, the string vibrates in the standing wave pattern shown. Assume the tension in the string and its mass per unit length do not change. Which of the following frequencies could NOT also produce a standing wave pattern in the string?A) 30 Hz B) 40 Hz C) 80 Hz D) 180 Hz

2. If the frequency of sound wave is doubled, the wavelength:A) halves and the speed remains unchanged.B) doubles and the speed remains unchanged.C) halves and the speed halves.D) doubles and the speed doubles.

3. Two waves pulses approach each other as seen in the figure. The wave pulses overlap at point P. Which diagram best represents the appearance of the wave pulses as they leave point P?

4. If the speed of sound in air is 340 m/s, the length of the organ pipe, open at both ends, that can resonate at the fundamental frequency of 136 Hz, would be:A) 0.40 m B) 0.80 m C) 1.25 m D) 2.5 m

5. As sound travels from steel into air, both its speed and its:A) wavelength increase B) wavelength decrease C) frequency increase D) frequency remain unchanged

6. A pipe that is closed at one end and open at the other resonates at a fundamental frequency of 240 Hz. The next lowest/highest frequency it resonates at is most nearly.A) 80 Hz B) 120 Hz C) 480 Hz D) 720 Hz

7. Assume that waves are propagating in a uniform medium. If the frequency of the wave source doubles thenA) the wavelength of the waves halves. B) the wavelength of the waves doubles. C) the speed of the waves halves. D) the speed of the waves doubles.

C.

D.

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Student:Mr. KhalilianAP PhysicsDue Date:

8. Multiple Correct. The diagrams above represent 5 different standing sound waves set up inside of a set of organ pipes 1 m long Which of the following statements correctly relates the frequencies of the organ pipes shown? Select two answers.

A) Cy is twice the frequency of Cx. B) Cz is five times the frequency of Cx. C) Oy is twice the frequency of Ox. D) Ox is twice the frequency of Cx.

9. Two wave pulses, each of wavelength λ, are traveling toward each other along a rope as shown. When both pulses are in the region between points X and Y, which are a distance λ apart, the shape of the rope is

(A) (B)

(C) (D)

Questions 10-11

A standing wave of frequency 5 hertz is set up on a string 2 meters long with nodes at both ends and in the center, as shown above.

10. The speed at which waves propagate on the string isA) 0.4 m/s B) 2.5 m/s C) 5 m/s D) 10 m/s

11. The fundamental frequency of vibration of the string isA) 1 Hz B) 2.5 Hz C) 5 Hz D) 10 Hz

12. Multiple correct: In the Doppler Effect for sound waves, factors that affect the frequency that the observer hears include which of the following? Select two answers.A) the loudness of the soundB) the speed of the source C) the speed of the observer D) the phase angle

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 22

Student:Mr. KhalilianAP PhysicsDue Date: 1995B6. A hollow tube of length L open at both ends as shown, is held in midair. A tuning fork

with a frequency f o vibrates at one end of the tube and causes the air in the tube to vibrate at its fundamental frequency. Express your answers in terms of L and fo.

a. Determine the wavelength of the sound.

b. Determine the speed of sound in the air inside the tube.

c. Determine the next higher frequency at which this air column would resonate.

The tube is submerged in a large, graduated cylinder filled with water. The tube is slowly raised out of the water and the same tuning fork, vibrating with frequency fo, is held a fixed distance from the top of the tube.d. Determine the height h of the tube above the water when the air column

resonates for the first time. Express your answer in terms of L.

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 23

Student:Mr. KhalilianAP PhysicsDue Date: 1998B5. To demonstrate standing waves, one end of a string is attached to a tuning fork with frequency 120 Hz. The other end of the string passes over a pulley and is connected to a suspended mass M as shown in the figure above. The value of M is such that the standing wave pattern has four "loops." The length of the string from the tuning fork to the point where the string touches the top of the pulley is 1.20 m. The linear density of the string is 1.0 x 10–4

kg/m, and remains constant throughout the experiment.a. Determine the wavelength of the standing wave.

b. Determine the speed of transverse waves along the string.

c. The speed of waves along the string increases with increasing tension in the string. Indicate whether the value of M should be increased or decreased in order to double the number of loops in the standing wave pattern. Justify your answer.

d. If a point on the string at an antinode moves a total vertical distance of 4 cm during one complete cycle, what is the amplitude of the standing wave?

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 24

Student:Mr. KhalilianAP PhysicsDue Date: FOUR IN FIVE

Questions 1-2

An object of mass m is initially at rest and free to move without friction in any direction in the xy-plane. A constant net force of magnitude F directed in the +x direction acts on the object for 1 s. Immediately thereafter a constant net force of the same magnitude F directed in the +y direction acts on the object for 1 s. After this, no forces act on the object.

1. Which of the following vectors could represent the velocity of the object at the end of 3 s, assuming the scales on the x and y axes are equal.

2. Which of the following graphs best represents the kinetic energy K of the object as a function of time?

3. The two blocks of masses M and 2M shown above initially travel at the same speed v but in opposite directions. They collide and stick together. How much mechanical energy is lost to other forms of energy during the collision?

a. Zero b. 12

Mv 2

c. 34

Mv 2

d. 43

Mv 2

e. 32

Mv 2

4. A satellite of mass m and speed v moves in a stable, circular orbit around a planet of mass M. What is the radius of the satellite's orbit?

a. GMmv b.

GvmM c.

d. GmM

v e. GmM

v2

Unit 9 – Mechanical Waves and SoundPractice and Notes Guide Packet, page. 25

Student:Mr. KhalilianAP PhysicsDue Date: FOUR IN FIVE

1. How does an air mattress protect a stunt person landing on the ground after a stunt?a. It reduces the kinetic energy loss of the stunt person. b. It reduces the momentum change of the stunt person.c. It increases the momentum change of the stunt person. d. It shortens the stopping time of the stunt person and increases the force applied during the landing. e. It lengthens the stopping time of the stunt person and reduces the force applied during the landing.

2. A child has a toy tied to the end of a string and whirls the toy at constant speed in a horizontal circular path of radius R. The toy completes each revolution of its motion in a time period T. What is the magnitude of the acceleration of the toy?

a. Zero b. 4 π2 R

T 2 c. πRT 2

d. g e. 2πg

3. A simple pendulum and a mass hanging on a spring both have a period of 1 s when set into small oscillatory motion on Earth. They are taken to Planet X, which has the same diameter as Earth but twice the mass. Which of the following statements is true about the periods of the two objects on Planet X compared to their periods on Earth?a. Both are shorter. b. Both are the same. c. Both are longer. d. The period of the mass on the spring is shorter, that of the pendulum is the same. e. The period of the pendulum is shorter; that of the mass on the spring is the same.

4. A steel ball supported by a stick rotates in a circle of radius r, as shown above. The direction of the net force acting on the ball when it is in the position shown is indicated by which of the following?