MK

Physical Science - Chapter 17 

Periodic Motion and Waves

17A Periodic Motion

  • @@Periodic Motion@@: motion that repeats in equal time intervals

  • @@Period@@: the time interval (T) for one complete cycle of the periodic motion

  • Periodic Motion of a Spring System

  1. Compressing the Spring
  2. The Expanding Spring
  3. Momentum Stretches the Spring
  4. Spring Compresses Again
  5. The Recoiling Spring
  • Using Periodic Motion
    • @@Damping@@: reducing the amplitude of periodic motion by applying a force that works against the motion
    • @@Damped Oscillator@@: a system that is designed to oscillate but includes a force to reduce the amplitude
    • @@Driven Oscillator@@: a system that is designed to oscillate at a constant amplitude by including a force to overcome frictional losses
    • @@Resonance@@: an increase in the amplitude of a vibration due to additional wave input

17B Waves

  • Defining Waves

    • @@Wave@@: a disruption that carries energy from one location to another
    • @@Mechanical Wave@@: a wave that carries energy through a physical medium
    • @@Electromagnet Wave@@: a disruption in an electromagnetic field that carries energy, even through the vacuum of space

  • Describing Waves

    • @@Crest@@: the highest point of a wave
    • @@Trough@@: the lowest point of a wave
    • @@Wavelength@@: the distance between two identical points on successive waves
    • @@Wave Height@@: the vertical distance between the trough and crest of a wave
    • @@Amplitude@@: the maximum displacement from the equilibrium position during periodic motion

  • Classifying Waves

    • @@Transverse Wave@@: a wave in which the disruptions move perpendicular to the direction of wave travel
    • @@Longitudinal Wave@@: a wave in which the disruptions are parallel to the direction of wave travel
    • @@Compression@@: a region of high density and pressure in a longitudinal (compression) wave
    • @@Rarefaction@@: a region of lower density and pressure in a longitudinal (compression) wave
    • @@Surface Wave@@: a wave that occurs along the interface between two media

  • Measuring Waves

    • @@Frequency@@: the number of waves or cycles that occurs per second

17C Wave Behavior

  • Behavior of Waves

    • @@Reflection@@: the bouncing of waves off a surface
    • @@Regular Reflection@@: reflection that occurs when a smooth surface reflects light rays in mostly the same direction; also known as specular reflection. A perfectly regular reflection is mirror-like, reflecting all rays and wavelengths uniformly
    • @@Diffuse Reflection@@: the reflection off a rough or uneven surface that reflects light rays in all directions
    • @@Refraction@@: a change in wave direction due to a change in a wave’s speed as it enters a new medium

  • @@Standing Wave@@: a wave that is moving even though the locations of the crests and troughs appear to be stationary

  • @@Doppler Effect@@: the perceived change in the frequency of a wave due to the motion of the wave’s source or of the receiver