Measuring Simple Harmonic Motion amplitude—the maximum displacement from equilibrium. (how high or low the wave gets) Doesn’t affect the speed of the wave. frequency—the number of cycles/waves per unit of time. Can be mentioned as revolutions, vibrations, oscillations, etc. period—the time it takes to execute a complete cycle of motion.

Measuring Simple Harmonic Motion The period of a simple pendulum depends on pendulum length and local gravitational acceleration Period of a Simple Pendulum in Simple Harmonic Motion

Measuring Simple Harmonic Motion Period of a Mass Spring System in Simple Harmonic Motion The period of a spring depends on the mass on the end and the stiffness (k) of the spring.

Section 12-3 Objectives Properties of Waves 1. Distinguish local particle vibrations from overall wave motion. 2. Differentiate between pulse waves and periodic waves. 3. Interpret waveforms of transverse and longitudinal waves 4. Apply the relationship among wave speed, frequency, and wavelength to solve problems. 5. Relate energy and amplitude.

Properties of Waves A wave is a motion of disturbance. medium—the material through which a disturbance travels. mechanical wave—a wave that moves through a medium such as liquid, gas, or solid.

Properties of Waves Wave Types pulse wave—a single, nonperiodic disturbance.

Properties of Waves Wave Types periodic wave—a wave whose source is some form of periodic motion. sine wave—a wave whose source vibrates with simple harmonic motion.

Properties of Waves Types of Waves transverse wave– a wave whose particles vibrate perpendicularly to the direction of wave motion. crest—the highest point above the equilibrium position. trough—the lowest point below the equilibrium position. wavelength—the distance between two adjacent similar points of the wave, such as from crest to crest or trough to trough. waveform—graphic representation of the shape of a wave that indicates its characteristics.

Anatomy of a T-wave

Properties of Waves Types of Waves longitudinal wave– a wave whose particles vibrate parallel to the direction of wave motion.

Properties of Waves Types of Waves longitudinal wave– a wave whose particles vibrate parallel to the direction of wave motion.

Properties of Waves Types of Waves V = f *λ V = wave speed (m/s), f = frequency (Hz), λ = wavelength (m)

Speed of Waves Sound- usually between 330m/s and 345m/s in “air”. Depends on the gas it’s in. Ex: Pure Hydrogen= 1284m/s, Carbon dioxide- 259m/s Sound- usually between 330m/s and 345m/s in “air”. Depends on the gas it’s in. Ex: Pure Hydrogen= 1284m/s, Carbon dioxide- 259m/s Light- 3 x 10 8 m/s, always. Light- 3 x 10 8 m/s, always. Light from the stars Light from the stars takes time to get to us. Seeing things from a loooong time ago with the help of new telescopes.

Wave Interactions Section 12-4 superposition– the combination of two or more overlapping waves. constructive interference—amplitude is the same sign, so they are added together to form a larger wave. superposition principle– when 2+ waves travel through a medium, the resultant wave is the sum of the amplitudes of the individual waves at each point. destructive interference—amplitudes are different signs, so they cancel either partly or all the way to form a smaller wave.

Superposition

Reflection reflection—the turning back of a wave at the surface of a substance. At a free boundary, waves are reflected. At a fixed boundary, waves are reflected and inverted.

Standing Waves standing wave—a wave pattern that results when two waves of the same frequency, wavelength, and amplitude travel in opposite directions and interfere. node—a point in a standing wave that always undergoes complete destructive interference and therefore is stationary. antinode—a point in a standing wave halfway between two nodes, at which the largest amplitude occurs.

Standing Waves

1 st Harmonic

2 nd Harmonic

3 rd Harmonic

4 th Harmonic

5 th Harmonic

Standing Waves

Use a wave game! r r r r (Level 4 is best for this concept) (Level 4 is best for this concept) And use: And use:

Sonic Boom When a sound wave is being produced by a moving object and that object is traveling at the speed of sound…we will look more into this topic in chapter 13. When a sound wave is being produced by a moving object and that object is traveling at the speed of sound…we will look more into this topic in chapter mons/e/e4/Dopplereffectsourcemovingrigh tatmach1.4.gif mons/e/e4/Dopplereffectsourcemovingrigh tatmach1.4.gif mons/e/e4/Dopplereffectsourcemovingrigh tatmach1.4.gif mons/e/e4/Dopplereffectsourcemovingrigh tatmach1.4.gif

Hearing Beats When two sounds are close, but not the same frequency, you will hear beats being produced. A keen ear can be used to tune instruments this way. When two sounds are close, but not the same frequency, you will hear beats being produced. A keen ear can be used to tune instruments this way. Djz6jnY Djz6jnY Djz6jnY Djz6jnY Click the above link to observe this phenomenon. Click the above link to observe this phenomenon.