1. Tuesday(01/05): Intro. to Ch. 14, Periodic Motion and Wave Properties.

HW: Read pages 375-82 and Solve prob. 70, 72, 74, 75, 79, 81, and 84 on

pages 397-98.

2. Wednesday(01/06): Wave equations and Wave Behavior.

HW: Read pages 382-90, Study page 395, and Solve prob.  88, 89, and 90

on page 399.

3. Thursday(01/07): Intro. to Ch. 15, Sound Waves, and the Doppler

Effect. HW: Read pages 403-10 and Solve prob. 52, 54, 57, 60, and 65

pages 425-26.

4. Friday(01/08): Lab on the Speed of Sound in Air. HW: Process all lab

data (Lab Report due Tuesday).

5. Monday(01/11): Complete Review Exercises in Lab handout.

HW: Finish Lab Report, due tomorrow (Tuesday).

6. Tuesday(01/12): The Physics of Music, Resonance, and Beats. Review

for Test. HW: Read pages 411-19, Study page 423, and Solve prob.  68, 74,

77, 79, and 82 on pages 426-27.

HW: Go to web-site for notes on Ch.16&17 - Light and Reflection.

WEBSITE NOTES: Physics I Honors. Ch. 14 & 15 - Waves and Sound.

1. In Simple Harmonic Motion (SHM), restoring force and acceleration are

maximum at maximum displacement and velocity is maximum at equilibrium.

2. A mass-spring system vibrates with SHM, and the spring force is given by

Hooke's Law: F = -kx, with k being the spring constant measured in N/m. This

leads to the equation for elastic potential energy which is PE_elas = ½kx².

3. The period of a mass-spring system depends only the mass and the spring

constant, T = 2π√(m/k) . The period of a pendulum depends only on the length

of the string and the acceleration due to gravity T = 2π√(l/g). For small angles

(<15^o), a pendulum swings with SHM.

4. Wave motion also has properties of SHM in that wave particles vibrate

around an equilibrium position as the wave travels.

5. There are three kinds of waves: transverse, longitudinal, and surface waves.

These are based on the movement of wave particles relative to the wave velocity.

6. For a transverse wave, vibrations are perpendicular to wave velocity. In a

longitudinal wave, vibrations are parallel to wave velocity. The third kind, surface

 waves, particles move both perpendicular and parallel to the direction of the

wave's motion.

7. Mechanical waves, such as sound waves or waves on a rope, for example

require a medium. Electromagnetic waves, such as light and radio waves, do not

need a medium.

8. Waves transfer energy, either by mechanical or electromagnetic means,

without the transfer of matter.

9. The shortest distance between points where the wave pattern starts to repeat

itself is called the wavelength, and is indicated by the Greek letter, lambda, λ.

10. A wave disturbance moves in straight lines in all directions away from the

source (rectilinear propagation). This allows us to use the distance-rate-time

equation d = v·t .

11. The frequency ( in sec.^-1 or Hertz, Hz.) of a wave, given by f, is the number of

vibrations per second of any one point on a wave.

12. Period, the reciprocal of frequency, T = 1/f , is the time for a wave to pass by.

13. The velocity of a wave, the distance a point on a wave moves in a unit time

interval can be calculated using the wave equation, v = f·λ.

14. The amplitude of a wave is the maximum displacement from the equilibrium

position.

15. The highest point above the equilibrium position is called the crest, and the

lowest point below is called the trough.

16. Energy transferred by a wave is proportional to the square of the amplitude.

17. The speed of a wave depends on the properties of the medium through which

it travels.

18. If two or more waves are moving through a medium, the resultant wave is

found by adding amplitudes together, point by point. This is known as the

Principle of Superposition.

19. Standing waves are formed when two waves having the same frequency,

amplitude and wavelength, travel in opposite directions in a medium and interfere.

20. When waves reach a boundary between two media, they are partially

transmitted and reflected. The amount of reflection depends on how much the two

media differ.

21. When a wave moves from a more dense to a less dense medium, the reflected

wave is erect. But in moving from less dense to more dense, the reflected wave is

inverted.

22. Maximum destructive interference produces nodes while maximum constructive

interference produces antinodes.

23. Waves are reflected from a barrier at the same angle, measured against the

normal, as they approach it.

24. The Law of Reflection states that the angle of incidence equals the angle of

reflection, angle(i) = angle(r) .

25. The spreading of waves around the edge of a barrier is known as diffraction.

26. The change in direction of waves at the boundary of two different media is known

as refraction.

27. Sound, produced by vibrating objects, is a longitudinal wave transmitted through

a gas, liquid, or solid.

28. A sound wave is an oscillation in the pressure of the medium, with the ear and

brain perceiving the amplitude as loudness or intensity, or I = P/(4πr²).

29. The frequency of a sound wave determines its pitch, and on the musical scale, two

notes that differ by one octave have pitches in ratio 2:1.

30. The Doppler shift is the change in frequency of a sound caused by the motion of

either the source, s, or detector, d. The equation is f_d = f_s((v – v_d)/(v – v_s)).

31. The amplitude of a sound wave is measured on a scale of decibels (dB), with

β=(10 dB)·log(I/I_o). The threshold of hearing is, I_o = 1.00x10^-12W/m² .

32. The speed of sound in air at 0.0^oC is 331.5 m/s, and increases by .60 m/s per

degree rise in air temperature. Speed depends on medium, see page 405.

33. An air column can resonate with a sound source increasing the loudness of the

source. A closed pipe resonates at odd multiples of λ/4 , while an open pipe resonates

at all multiples of λ/2 .

34. Two sound waves with almost the same frequency produce a beat note, found by

subtraction in absolute value, f_B= lf₁ - f₂l .

35. Most sounds consist of waves with more than one frequency with the quality of the

wave called timbre.

36. And still, we need these steps to solve any problem in Physics:

(i) read the problem and identify the given variables

(ii) determine what you are asked to solve for

(iii) find the correct motion formula to use

(iv) use algebra to isolate the unknown

(v) substitute-in the given information and simplify.

Answers to Homework:

Page 397-8: #70. .12 m, #72. .29 m, #74. .21 m, #75. 8.3 s,

#79. 1.5 km/s, 1.0 µs, 1.0 µs, #81. 1350 m, #84. (checked in class)

Page 399: #88. 2.4 s, #89. 5.7x10^-7 m, #90. 190 to 550 m, 2.78 to 3.4 m

Page 425-6: #52. 1.7 km, #54. 5.2 km/s, #57. 5.707 m,

#60. 110 dB, reduce by 40 dB, #65. .353 mm

Page 426-7: #68. 350 Hz, #74. 442 and 448 Hz, #77. 255 m/s, 392 and 588 Hz,

#79. 437.5 or 442.5 Hz, #82. 1.0 µN, 1.5 µN, .58 Pa.

THE HONORS PHYSICS SEMESTER 1 ARCHIVES Ch.1: Physics Intro. Ch.2&3: Linear Motion. Ch.4&5: Forces. Ch.6: 2-Dim Motion. Ch.7: Gravitation. Ch.8: Rotary Motion. Ch.9: Momentum. Ch.10&11: Work&Energy. Ch.12: Thermal Energy. Ch.13: States of Matter. Semester Review. Ch.14&15: Waves&Sound. Ch.16: Study of Light. Ch.17&18: Mirrors & Lenses. Ch.19: Light Interference.