Today 1/16 • Waves • Interference of Waves • HW: 1/16 HW Handout “Superposition” Due Wed, 1/22 (beginning of class) • Read: Ch 16.1,2,5 Ch 17.1,2 • Suggest: Problems 16-1,2,3,4,5,8 • Note: This “lecture” is mostly animations and is more than 80 slides long! Beware the print button!
Things to think about: Consider a traveling wave: sound, light, football stadium, water... How would you define a “wavelength?” How would you define a “frequency?” How would you define a “wave velocity?” How does the direction of the wave’s motion compare to the direction of the individual particle’s motion? What happens when two waves run into each other?
How does the direction of the wave’s motion compare to the direction of the individual particle’s motion? Wave moves right while particles move up and down.Called a “transverse wave” Examples are light, water, and football stadium, sound is a “longitudinal wave.”
Wavelength () = ? = 8 units Wave Velocity (v) = ? Direction is to the right, v = x/t x is and t is T, the time for a particle to go through one complete oscillation, as in SHM. v = /T v = f Frequency, f = 1/T also as in SHM.
? ? ? Superposition!!! Green wave says move up but blue wave says move down so... Particle does not move!! Superposition means “superimpose” all effects at a chosen location then add them up (as vectors) to get the “net” effect at that location.