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Unit 4: Sound and Waves. 11.2 Graphs of Harmonic Motion. Reading Harmonic Motion Graphs. Seeing a pattern of cycles on a graph is an indication that harmonic motion is present Periodic motion : graphs repeat every period (from crest to crest) Amplitude on a graph
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Unit 4: Sound and Waves 11.2 Graphs of Harmonic Motion
Reading Harmonic Motion Graphs • Seeing a pattern of cycles on a graph is an indication that harmonic motion is present • Periodic motion: graphs repeat every period (from crest to crest) • Amplitude on a graph • Distance between highest and lowest points • Period of a graph • Time difference between the beginning of the cycle and the end
Circles and Harmonic Motion 11.3 Simple Mechanical oscillators Pendulum Force that always pulls the pendulum back to the center comes from its weight Spring Springs of a car are compressed and extended in rhythmic patterns String Such as a guitar string, it will vibrate and make waves • Cycles of circular motion always have a length of 360 degrees • Phase: where the oscillator is in its cycle
Scientist Spotlight • Katherine Johnson • Born in 1918 • Hired as a mathematician by a government agency that became NASA • Determined trajectories for manned and unmanned spacecraft • Helped plan the Apollo missions and developed their emergency navigation system