when two waves arrive at the same point exactly in phase; that is, the crests of the two waves are precisely aligned, as are the troughs
destructive interference
when two identical waves arrive at the same point exactly out of phase; that is, precisely aligned crest to trough
fixed boundary condition
when the medium at a boundary is fixed in place so it cannot move
free boundary condition
exists when the medium at the boundary is free to move
fundamental frequency
lowest frequency that will produce a standing wave
intensity (I)
power per unit area
interference
overlap of two or more waves at the same point and time
linear wave equation
equation describing waves that result from a linear restoring force of the medium; any function that is a solution to the wave equation describes a wave moving in the positive x-direction or the negative x-direction with a constant wave speed v
longitudinal wave
wave in which the disturbance is parallel to the direction of propagation
mechanical wave
wave that is governed by Newton’s laws and requires a medium
node
point where the string does not move; more generally, nodes are where the wave disturbance is zero in a standing wave
normal mode
possible standing wave pattern for a standing wave on a string
overtone
frequency that produces standing waves and is higher than the fundamental frequency
pulse
single disturbance that moves through a medium, transferring energy but not mass
standing wave
wave that can bounce back and forth through a particular region, effectively becoming stationary
superposition
phenomenon that occurs when two or more waves arrive at the same point
transverse wave
wave in which the disturbance is perpendicular to the direction of propagation
wave
disturbance that moves from its source and carries energy
wave function
mathematical model of the position of particles of the medium
wave number
wave speed
magnitude of the wave velocity
wave velocity
velocity at which the disturbance moves; also called the propagation velocity
wavelength
distance between adjacent identical parts of a wave