P12: Waves

• Mechanical waves


  Require a medium to travel through
• Electromagnetic waves


  Can travel through vacuums as well as mediums
• Speed of light


  3 x 10^8 m/s
• Longitudinal waves


  Vibrations are parallel to the direction of energy transfer
• Transverse waves


  Vibrations are perpendicular to the direction of energy transfer
• Speed of sound


  340 m/s
• Wavelength of transverse waves


  Distance from one crest to another adjacent crest
• Wavelength of longitudinal waves


  Distance from one compression to another adjacent compression
• Amplitude


  Maximum displacement from equilibrium
• Human hearing range


  20Hz - 20,000Hz
• Primary seismic waves


  Longitudinal

  Can pass through solids and liquids

  Fast
• Secondary seismic waves


  Transverse

  Can only pass through solids

  Slow
• Specular


  Reflection off of smooth surfaces
• Diffuse


  Reflection off of rough surfaces