4/19/11

Post date: Apr 19, 2011 1:1:31 PM

• • Bell Ringer: What happens to a wave when it encounters a change in media?

  • Anatomy of a wave

    • Period (T) - the time for a particle's motion to repeat - measured in seconds

    • Frequency (f) - how many cycles occur in one second - measured in Hertz (hz)

    • Equilibrium - the resting position of the medium

    • Peak - the highest point on the wave

    • Trough - the lowest point on the wave

    • Wavelength (lambda) - distance between like points on the wave (e.g. peak-peak or trough-trough) - measured in meters

    • Velocity (v) - how quickly the wave moves down the line - measured in m/s

    • Amplitude (A) - a wave's maximum distance from equilibrium - measured in m

  • Equations

    • Frequency and Period

      • are the inverse of each other

      • f = 1/T

    • The wave equation

      • relates wave speed, frequency, and wavelength

      • v = f * wavelength

  • Page 304:1-4 due tomorrow

  • Remember that v=d/t

  • The speed of light is approximately 3.00 x 10^8 m/s.

Reflection

• • When a wave hits a barrier, some of it may be reflected

  • Reflected waves can be inverted (upside down) or erect (right-side up)

  • Standing Waves

    • When a continuous wave of just the right frequency is reflected back from a barrier and interferes with itself, a standing wave is created

• • • On a standing wave, the parts that don't move are called nodes and the parts that move most are anti-nodes

    • The distance from one node to the next, or from one anti-node to the next is half of a wavelength.