Physics: Vibration and Oscillation

Vibration and Oscillation

• Vibration: repeated back-and-forth motion of a particle when displaced from its equilibrium position
• Oscillation: periodic or repetitive motion

Examples of Vibrations

• Atoms and molecules of solids vibrate from their equilibrium positions
• Guitar string vibrates and produces sound when plucked
• Pebble thrown in a calm lake surface produces concentric ripples that expand from the source of impact
• Tuning fork, swinging pendulum, and oscillation of a radio's loudspeaker

Vibration and Sound

• Vibration displaces particles in the medium, allowing them to move back and forth parallel to the direction of the wave
• Repeated vibration of particles reaches human ears and is interpreted by the brain as sound
• Example: plucked guitar string displaces surrounding air particles, creating alternating regions of compressed and spread-out particles

Spring-Mass System

• Block attached to a spring exhibits vibrations when disturbed
• Stretches up to a certain distance when pulled, then returns to equilibrium position before contracting
• Continuously expands and contracts at regular intervals until it eventually stops vibrating

Vibrations and Waves

• Vibrations or oscillations are the sources of waves
• Waves are disturbances or vibrations that travel from one point to another
• Examples: sound waves, water waves, and light

Types of Waves

• Transverse waves: particles in the medium vibrate perpendicular to wave propagation
  • Example: light
• Longitudinal waves: particles move parallel to the direction of wave propagation
  • Example: sound waves

Types of Waves Based on Medium

• Mechanical waves: require a medium to propagate
  • Examples: waves produced on a string or a slinky, sound waves
• Electromagnetic waves: do not require a medium and can travel through a vacuum
  • Examples: radio waves, microwave, visible light, ultraviolet, X-rays, and gamma rays

Parts of a Wave

• Crest: highest point in a wave
• Trough: lowest point in a wave
• Amplitude: distance between the equilibrium position and the highest or lowest point in a wave
• Wavelength: distance between two successive identical points in a wave

Frequency and Wavelength

• Frequency: number of waves that pass through a fixed point per unit time
  • Measured in 1/s or hertz (Hz)
• Inverse relationship between wavelength and frequency: longer wavelengths have lower frequencies, and shorter wavelengths have higher frequencies

Energy Transfer

• Waves transfer energy but not matter itself
• Example: particles in air move back and forth as energy is transferred from the source to the receiver
• Amplitude reflects the amount of energy carried by the wave: larger amplitude means higher energy