Good Vibrations https://youtu.be/W4s2UwKm7dc 1. Use three different words / phrases to describe the motion of the pendulum. 2. Sketch the pendulum in motion in the space below. Indicate where the equilibrium position of the pendulum is. 3. What are some ways we could quantify the motion of the pendulum? (Motion involves distance and time.) Discuss with the people around you! 4. If you were to plot a position vs. time graph of the pendulum, what would it look like? Sketch a graph of position vs. time below. 3. What are some ways we could quantify the motion of the pendulum? (Motion involves distance and time.) The amount of time it takes to complete one cycle is called the period. Period = T 3. What are some ways we could quantify the motion of the pendulum? (Motion involves distance and time.) The amount of time it takes to complete one cycle is called the period. Period = T The number of cycles the pendulum completes in one second is called the frequency. Frequency = f How could we use the information from the period of the pendulum to figure out its frequency? Consider: What is the frequency of a pendulum that has a period of 0.5 seconds? How could we use the information from the period of the pendulum to figure out its frequency? What is the relationship between frequency and period? Consider: What is the frequency of a pendulum that has a period of 0.5 seconds? Position vs. Time Graph of Pendulum What is a wave? A wave is an oscillation or repeated motion that travels through some medium and carries some kind of information or energy. Parts of a Wave Wavelength () The length of one complete cycle. Parts of a Wave Wavelength () The length of one complete cycle. Amplitude (A) The maximum amount of displacement of a particle of the medium from its equilibrium position. Parts of a Wave Wavelength () The length of one complete cycle. Amplitude (A) The maximum amount of displacement of a particle of the medium from its equilibrium position. Crest The maximum amount of positive / upward displacement from equilibrium. Parts of a Wave Wavelength () The length of one complete cycle. Amplitude (A) The maximum amount of displacement of a particle of the medium from its equilibrium position. Crest The maximum amount of positive / upward displacement from equilibrium. Trough The maximum amount of negative / downward displacement from equilibrium. Waves Transfer Energy, Not Matter When energy is transferred by a wave from a vibrating source to a distant receiver, no matter is transferred between the two points. Two Types of Waves Transverse Wave Transverse waves carry energy when the parts of the wave move away from equilibrium in a direction perpendicular to the motion of the wave. An example of a transverse wave is an electromagnetic wave (light). Longitudinal Wave Longitudinal waves carry energy when the parts of the wave move away from equilibrium in a direction parallel to the motion of the wave. An example of a longitudinal wave is a sound wave. The Physics of Waves https://youtu.be/gi7SeYefIVI Review Harmonic, or repeated, motion is all around us and can be quantified by measuring the frequency of the cycle. A wave is a repeated motion that travels through some medium and carries some kind of information or energy. A wave carries energy, not matter. The wave disturbance travels while the stuff in the wave oscillates around its equilibrium position. Transverse waves carry energy when the parts of the wave move away from equilibrium in a direction perpendicular to the motion of the wave; longitudinal waves carry energy when the parts of the wave move away from equilibrium in a direction parallel to the motion of the wave.