Download Waves

WAVES
Regular,
Rhythmic
disturbance in a
field or medium
where a transfer
of energy occurs
WAVE TYPES
Mechanical: needs a medium (example:
water waves, sound)
Electromagnetic: Alternating electric and
magnetic fields. Does not need a
medium ( radio waves, light)
Wave Motion
1) Longitudinal
waves: Vibration is
parallel to the
motion of the wave.
Also referred to as
a compression
wave.
WAVE MOTION
2) Transverse Wave:
Vibration is
perpendicular to
the motion of the
wave.
What type is each?
Sound waves are
mechanical waves
because they need air
to travel in. They are
also longitudinal
because air vibrates
parallel to the direction
of the sound.
Water waves are
mechanical because
they need a medium.
They are also
transverse because
the water moves
perpendicular to the
wave which is moving
towards shore.
Aurora Borealis is an
electromagnetic
wave caused by the
magnetic field of the
earth. It is also a
transverse wave they
are light waves.
TRANSVERSE WAVES
Crest
Amplitude
Trough
Wavelength
TERMS
Pulse – A single wave disturbance
Amplitude – Maximum perpendicular
displacement
Wavelength - Distance between identical
points on consecutive waves. Measured
in meters.
(Lambda λ )
Frequency – Number of waves that pass
a point per second.
Unit: waves/sec or Hertz (Hz)
Period - Time for one wave cycle.
Unit: seconds
T = 1/ f
FORMULA!!!!!
Speed or Velocity of a wave:
V=fλ
v – velocity (m/s)
f – frequency (Hz)
λ – wavelength (m)
Sample problems:
Ex: The Sears building in Chicago sways back
and forth 6 times in one minute.
a) What is the period of the building?
b) What is the frequency of the building?
T = time/sways
T = 60sec/ 6 sways
T = 10 sec
f = 1/T
f = 1/10 = 0.1 Hz
Ex: A sound wave traveling at 340m/s has a
frequency of 1029Hz. What is the
wavelength of the sound wave?
v = fλ
340m/s = 1029Hz (λ)
λ = 0.33 m