Displacement:
is the distance
that the wave moves the medium away
from its equilibrium position.
Amplitude:
is the maximum
displacement
from the equilibrium.
Cycle:One
complete to and fro motion
of a vibration.
Frequency:
is the
number of complete revolutions per
second.
T=1/f
where f is frequency and T is period. w=2pf
where
w
is angular velocity.
Period:
is the
time required for one complete
revolution.
Wavelength:
is defined as the
distance from any point in the wave to the next successive
identical point in
the wave.
Wave
Velocity:
depends
on the medium
and is defined by v = (elastic factor/inertia
factor)1/2. It can also be calculated by v = f
l.
Transverse
Wave:
A wave in which the disturbance
is at a right angle to the direction of
motion
of the wave.
Longitudinal
Wave:
A wave in which the disturbance
is parallel to the direction of motion of
the wave.
Compression:
The place in a longitudinal wave where the
particles
of the medium are gathered closer together than they would be
without the wave present.
Rarefaction
(Expansion):
The place in a longitudinal wave where the
particles
of the medium are further apart than they would be without the
wave present.
Reflection:
is the bounce
that a
wave does when it hits a barrier it can not
cross.
Wave
fronts:
are the
leading edge of wave disturbances
as they pass through a medium. Often the material in a wave
crest is referred to as a wave front.
Refraction:
is the change
in propagation path and wavelength
that a
wave undergoes when it passes from a medium where it has one
velocity into a medium where it has a different
velocity.
Interference:
the constructive
and destructive addition of two or more waves as they pass
through the same medium at the same time.
Principle
of Superposition:
is the statement that waves
can be added as a series of vectors that form the resulting
wave.
Usually the crest is considered a positive
displacement.
Destructive
Interference:
is the result of two or more waves in the same medium being
partially
out of phase or totally out of phase and resulting in a reduced
amplitude wave
after superposition.
Constructive
Interference:
is the result of two or more waves in the same medium being
in phase
and resulting in a double amplitude wave
after superposition.
In
Phase:
is the name given to two
waves that align crest to crest and trough to
trough.
Out of
Phase:
is the name given to two different conditions:
two
waves that align crest to trough and trough to crest
and
are completely out of phase.
two
waves that align in any way other than in phase
and
are partially out of phase.
Partially
Destructive:
destructive interference that occurs when waves are partially
out of phase.
Standing
Wave:
a type of interference
that occurs when a wave interferes with its own
reflection.
Nodes:
are points
of minimum motion in a standing wave.
Antinodes:
are points
of maximum motion in a standing wave.
Key
Concepts:
Total
Mechanical Energy :
The total
mechanical energy stored in a wave is
proportional to the square of the wave
amplitude.
The Law of
Reflection:
The angle
of incidence is equal to the angle of
reflection.
Wave
Velocity:The
velocity of a mechanical wave
is dependent on the elasticity and the inertia of the
medium. The formula that
defines the velocity is v =
(elastic force factor/inertia
factor)1/2
