PHY 102 1st EditionOutline of Last LectureI. Simple Harmonic Oscillationa. SHO definitionb. Periodc. Examplesi. Hooke’s Lawii. PendulumII. Waveform Termsa. Properties of wavesb. DefinitionsIII. Sound as an Analogya. Tuning forkb. Sound wavesc. Types of wavesIV. Wave FormsOutline of Current Lecture i. Continued Examplesa. Example 1b. Example 2c. Example 3These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.d. Example 4ii. Other Properties of Wavesa. Polarizationb. Diffractionc. Interferenced. Doppler Shift/Effectiii. Light Propertiesiv. Electricitya. Example Dischargesb. Electrical Charges c. Electrical Field Strengthd. Coulomb’s LawCurrent LectureI. Continued Examplesa. The period of oscillation is 2.7 secondsF=1/tF = 1/2.7 secondsF = 1/2.7 Hertz or Hzi. 1 Hertz = 1 cycle/secondii. Period is the reciprocal of frequencyb. 3 wave crests pass a point every 10 seconds – what is the frequency of the crests?F = oscillations/second3 oscillations/10 seconds = .3 Hzc. What is the appropriate frequency of a 6.563 nm wavelength of light? (1 nanometer = 1x10-9 m and c = 3x108 m/s)λ x F = speed of light = 3.0x108m/si. Wavelength x frequency = speed of the propagation of the waveii. One speed in the universe is constant = light (3.0x108m/sd. A tidal wave is 3m high. How energetic is a 6m high tidal wave in comparison to the 3m wave if both are traveling at the same speed?E = kA2So, a wave twice as high will have 4 times as much energy because of the A2.e. How fast is a wave moving if f = 3Hz and λ = 2.3 mF = 3Hzλ = 2.3 m(2.3 * 3) = 6.9 m/sλ f = vII. Other Properties of Wavesa. Polarizationi. Polarized sunglasses cost more because they are like picket fences; the light can only come through one wayii. When light passes through one lens which allows vertical waves, the next lens will be one that only allows horizontal waves, blocking (almost) all waves of lightiii. Oscillation can be up and down, side to side, spiraliv. Electric field vectors can align and become “polarized”v. When radiation comes through, it reduces the glare dramaticallyvi. Used in astronomy to measure magnetic fields in spaceb. Diffraction – dispersal of lighti. When the slight that a ray of light passes through approaches the size of the ray of light, the light diffracts and dispersesii. Example of a harbor1. When a wave in a harbor passes through a small opening into the shore, the wave starts small and begins to ripple and disperse through the water as it approaches the shore2. Intensity v. distance graph looks like lots of small curves because as the distance grows larger, the intensity of the wave grows and diminishesc. Interference – 2 waves coming together – 2 diffraction patterns intersectingi. Intensity v. distance graph looks very random because the two waves can intersect at the crest points or at the bottom and a crestii. The intensity of a sound varies at different positions of the observer because of interference of wavesiii. Where the crests of a wave intersect, the wave doubles and the sound is observed louderd. Doppler Effect – sound shifts because of position of the heareri. Also observed in light when galaxies appear red because the universe is expanding and they are moving farther awayii. Pitch changes in racecars, trains, due to the Doppler shift/effectIII. Lighta. Acts as a particle and a wave depending on the scalei. Large scale: particle-like property: light travels in a straight line and creates distinct shadowsii. Measured in photons which have properties of a particle while containinga wave of light insideiii. Small scale: wave-like property (single slit demo) and interference (doubleslit demo)IV. Electricitya. Electrostatici. Example discharges1. Lightning2. “foot dragging”3. Static cling in dryersii. Electrical charges come in two types, + and =1. Amber (Greek called Electron) is associated with –2. Glass associated with +3. Charging: by induction and conductionb. Action at a distance – applying a force without touching the other objecti. Repelling is from the same chargeii. Attracting is from the opposite chargec. An object has equal photons and elctrons, when electrons are added the object becomes negatively chargedd. An object can become polarized when the electrons gather in certain areasi. Induction – not touchingii. Conduction – touchinge. More moisture in the air, the shorter time the electricity is held in an objectV. Electrical Chargesa. Negative (electron) – when electrons are addedb. Positive (proton) – when electrons are taken awayc. Charge is measured in Coulombs, ci. Absolute value of C *s = ampere = 6.215x1018 electrons/secondd. Quantities of chargei. Electron = -1.6 x 10-19ii. Proton = +1.6 x 10-19VI. Electrical Field Strengtha. E = Fe/q by definition (force per unit charge)b. Units of E are N/cc. Parallels W = mg where g = gravitational field strengthd. Electric field linesi. Directed from positive to negative chargeii. Show the path that a positive unit test charge would take1. Test charge = one single proton2. Field liens appear to exist but have no physical forme. Coulomb’s Lawi. Fg = GM1M2/r2Fe = kq1q2/r2 or kQq/r2First worked out as a torsion