PHYS 105 1nd Edition Lecture 9Outline of Last Lecture I. Doppler Effect and Intensity Outline of Current Lecture II. Resonances of physical systemsIII. Standing Waves IV. Sound Pressure Current LectureI. Resonances of physical systems- Resonance: Constructive interference o Wave and its reflection can interfere constructively at certain frequencies o Provide natural sound frequencies for music instruments- Resonance of a vibrating system includes:o Resonance Frequency foo Bandwidth [Change in frequency] [2−¿ f1f¿ of frequencies at 0.71 of maximum amplitude]o Q-Value of resonance = f0/∆ fII. Standing Waves- Standing wave: Incoming and reflective waves can interfere and produce standing wave modes/resonances o Has regions of minimum amplitude = Nodeso Has regions of maximum amplitude = Antinodes- Standing waves on a string = Standing waves are resonances of the vibrating system- Standing wave = Stationary and wave - Wave reflection: Wave reflection changes phase 180° from a fixed end and no phase change from a free end - Velocity of wave on a stringov =√TμThese 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.III. Sound Pressure -ρ = pressure is force per unit area- Sound pressure is the pressure exerted by the sound wave - Unit = Newton per unit area or N/m^2 or Pascal - When displacement is high or low; pressure is zero- When pressure is high or low; displacement is zero- Pressure disturbance at the open end of a pipeo Is a fixed end- Pressure disturbance at the closed end of a pipeo Is a free
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