General Wave Motion
Waves vs Particles
Particles can collide: stick together or bounce off
each other
Waves pass through each other, either adding up
or canceling out: superposition
Since (most) waves are ultimately made up of
particles, how does superposition happen?
WAY too much for us!
Now: Lots of jargon . . . 
Wave motions
Wave pulse: One (and only one) pulse
moves in a “wavy” fashion.
Wave train: A collection of many pulses.
Sinusoidal wave: A wave train of a very
particular type, and the one which we will
consider [not (too) mathematically].
Fig. 15-14, p.310
Types of waves
Transverse waves: particles that make up the
wave are moving perpendicular to the motion of
the wave. (Waves on a string)
Longitudinal waves: particles that make up the
wave are moving in the same direction as the
motion of the wave. (Sound waves)
Others: combination of transverse and longitudinal
(Water waves)
Fig. 16-1, p.324
Superposition
Waves pass through each other and add up:
Constructive Interference
Waves pass through each other and cancel
out: Destructive Interference
Fig. 15-13, p.310
Fig. 15-12, p.308
“Sinusoidal” waves
Defined by wavelength “λ”; period “T”,
frequency “f”, amplitude “A”, and speed
“v”.
f = 1/T and v = λ/T so v = fλ.
This last equation is true for ALL sinusoidal
waves, although “v” is determined by the
particular type of wave.
Fig. 15-15, p.310
“v” determined by what is waving
Waves on a string: v = √(T/μ) “μ” is the
mass density of the string, and “T” is the
tension in the string.
Sound waves: v ≈ 340 m/s near the ground
on earth; actual value depends on many
things.
Electromagnetic waves: v = c = 3 × 108 m/s