2. Wave Basics Or, How to Destroy a Slinky Without Even Trying… AP – Ch 16 & 17

3. MT KNOTES Counts 20% of FINAL GRADE! 40-45 MG + 3/5 SA ANY block except 5 & 7 LAST Open-Note Exam of year. NO CURVE.

5. Shtuff Topics left – Waves & Sound (Current) MidTerms – Electricity – Review & AP Exam

6. Basic Terminology Simple Harmonic Motion (SHM) – Anything that vibrates with periodic motion – Has an equilibrium position – Obeys Hook’s Law

16. Basic Terminology Wavelength Wavelength – DUH! – Displacement of a sinusoidal periodic wave along the independent coordinate. – i.e. The length of the wave. ‘ ’.

17. Basic Terminology Pulse Pulse – Single disturbance – ½ Pulse

18. Basic Terminology Period – Time required for one complete wavelength. – ‘T’ – Unit - Seconds

19. Basic Terminology Frequency Frequency – # wavelengths per second – f = 1/T – Unit – 1/sec, sec -1, Hz (Hertz)

20. Basic Terminology Amplitude Amplitude – Disturbance along the vertical. – Height of wave as measured from x-axis A

23. Phase Shift

25. Text p288

27. Basic Terminology Velocity of waves?

28. Energy in SHM Just like anything else:

29. Text p290

30. LAB 25 Following are old, & I mean OLD, pix of the LAB. Please, no silly comments about being a poor photographer or the ‘retro’ look…

33. LAB 25 OLD Camera Stuff.

34. MT KNOTES Counts 20% of FINAL GRADE! 40-45 MG + 3/5 SA ANY block except 5 & 7 LAST Open-Note Exam of year. NO CURVE. Monday PM Review

35. MT KNOTES Topics 1.2-D Kinematix (Projectile) 2.FMA 3.MV & E 4.Circles 5.Gravitation (L &  interspersed…)

36. KNOTES AP EXAM #5 – WHEN? [24 hr period] ~20 MG & 1/2 SA – Waves

37. Figure 2 4.What does a specific point on a slinky do as a pulse goes by?

38. How many pencils?

39. Figure 5 6.What is observed when two similar pulses (same amplitude) are sent down the slinky, one from each end, oriented in the same direction, at the same time.

40. 7.When pulses are generated from each end, do they pass through or reflect back from each other? They pass through each other.

41. Figure 4 The superposition of two equal and opposite pulses on a coil spring. In the fifth picture they almost cancel each other.

42. Less Into More Dense Material When a pulse is sent from the end of a slinky, what is observed?

43. More Into Less Dense Material When a pulse is sent from the metal end of a slinky, what is observed?

44. Superposition

46. Types of waves Transverse

47. Types of waves Longitudinal (Compressional)

48. Types of waves Surface (Water)

49. Superposition

51. Waves -Advanced Stuff Tighten your seatbelt… It’s getting’ bumpy!

52. Advanced Wave Stuff SHM – Follows F=-kx

53. Advanced Wave Stuff SHM – Follows F=-kx

55. Advanced Wave Stuff SHM - Energy

56. Advanced Wave Stuff SHM – T & f -

57. Advanced Wave Stuff SHM – T & f

58. Advanced Wave Stuff SHM – T & f

59. Advanced Wave Stuff SHM – Pendulumaeii

60. Types of waves Transverse

61. Types of waves Longitudinal (Compressional)

62. Types of waves Surface (Water)

63. Earthquake (Rayleigh W)

64. Standing Wave A wave that reflects on itself…

65. Wave reflection

66. Advanced Wave Stuff Fundamental f’s

67. Ch16 STOP HERE…

68. Ch 17: Sound

69. Advanced Wave Stuff SHM – Resonance – V sound Demo

70. Advanced Wave Stuff SHM – Resonance – V sound Demo

71. Advanced Wave Stuff Sound Intensity – Logarithmic Function (HUH?) –  =10 log I/I o I o = 1 x 10 -12 W/m 2 Chart pg 475

72. Intensity I (W/m 2) Intensity  (dB) Threshold of human hearing 1 x 10 -12 0 Leaves rustling1 x 10 -11 10 Whisper1 x 10 -10 20 Normal Conversation @ 1 m 1 x 10 -6 60 Inside closed car1 x 10 -4 80 Car w/o muffler1 x 10 -2 100 Live rock concert 1120 Pain10130 Taylor Mad1 x 10 488 5000 BELLS 0 1 2 6 8 10 12 13

73. Decibel (dB) Scale This scale is a logarithmic scale used for measuring the intensity of sound. The threshold of hearing is assigned a sound level of zero decibels. Intensity (W/m 2 )Intensity (dB) 1 x 10 -12 0 1 x 10 -11 10 1 x 10 -10 20

74. Decibel (dB) Scale Intensity Intensity (W/m 2 ) (dB) 1 x 10 -12 0threshold of hearing 1 x 10 -11 10normal breathing 1 x 10 -10 20average whisper (2m) 1 x 10 -9 30empty theatre 1 x 10 -8 40residential area-night 1 x 10 -7 50quiet restaurant 1 x 10 -6 602-person conversation 1 x 10 -5 70busy street traffic 1 x 10 -4 80vacuum cleaner

75. Decibel (dB) Scale Intensity Intensity (W/m 2 ) (dB) 1 x 10 -3 90loud stereo 1 x 10 -2 100concert hall 13 th row 1 x 10 -1 110pneumatic chisel 1120max level rock group 10130threshold of pain 1 x 10 2 140military jet taking off 1 x 10 3 150wind tunnel 1 x 10 4 160instant breaking ear drum

76. A log excursion…

77. Beats WaWa sound produced with 2+ sounds of close f’s.

79. External Site Beat frequency @ 330Hz +

80. Advanced Wave Stuff Sound Intensity Problems? – One sound produces a  1 = 90dB and another is  2 = 93dB. What is the ratio I 2 /I 1 ?

84. Advanced Wave Stuff Doppler Effect? – Occurs when a sound or an observer moves in the direction of the sound! (Say WHAT?) Sirens, Moving cars, Planes… Resonance tube Demo Tuning Fork Demo

85. Ugly Doppler Math

86. = Apparent Frequency = Actual Frequency = Object’s Velocity = Source Velocity = Sound Velocity TOP Sign = TOWARD

87. Apps & Probs A little pot-bellied kid is standing in the waves unattended. He notices 10 waves crash against his little chubby legs in 2 minutes. What is the frequency of these ocean waves?

89. Apps & Probs Two boats are hanging out 10 meters from each other. As the waves go by, one boat is at max up while the other is max down and no crests are between them. What’s the wavelength of the water waves?

91. Apps & Probs A boat is anchored. Over the side is a rope ladder with rungs one foot apart and there’s 8 of them visible above the waterline. The tide comes in and rises at a rate of ½ foot per hour. After 5 hours, how much of the rope ladder is still visible above the waterline?

92. DUH!

93. Apps & Probs The wavelength of a sound in air is 2.74m @ 20 o C. What is its wavelength if it enters fresh water at 20 o C?