intro to waves - physicstfnhonorsphysics.weebly.com/.../intro_to_waves-honors.pdf · 2019. 11....
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a wave
is a rhythmic disturbance that
carries/transfers energy through
matter or space
A repeating movement
Mechanical Waves
require a medium
medium: the matter through which a wave travels examples: water, air, anything made of matter
waves transfer energy from one point to
another with little or no permanent
displacement to the particles in the medium
Molecules pass energy along to neighbor,
who then passes energy to neighbor, etc.
All waves are produced by VIBRATIONS
Two Types of Mechanical
Waves:
1. Transverse Waves
2. Longitudinal/Compressional
Waves
Transverse Waves
waves that propagate (or move) perpendicular to the
direction of travel
crest
the point on the medium that exhibits the
maximum amount of positive or upward
displacement from the rest position
trough
the point on the medium that exhibits the maximum
amount of negative or downward displacement from
the rest position
amplitude
the maximum displacement of a particle on the medium
from its equilibrium position
wavelength
the length of one wave is measured
from a point on one wave to the same
point on the next wave
trough to trough
crest to crest
midpoint to midpoint
Anatomy of a Transverse Wave
Label the following parts of a transverse wave in your
notes:
equilibrium
crest
trough
amplitude
wavelength
Longitudinal Waves
waves that propagate (or move) parallel to the direction
of motion
compression
a point on a medium through which a longitudinal wave
is traveling that has the maximum density
rarefaction
a point on a medium through which a longitudinal wave
is traveling that has the minimum density
Anatomy of a Longitudinal Wave
Label the following parts of a
longitudinal wave in your notes:
compression
rarefaction
wavelength
Describing a Wave & Wave Speed
Frequency (f): the number of vibrations an object
makes in a unit of time (generally one second)
the unit of frequency is Hz = 1
𝑠
𝑓 =𝑣𝑖𝑏
𝑡
Period (T): the time needed to complete one vibration
(measured in seconds)
𝑇 =𝑡
𝑣𝑖𝑏
The Sears Tower sways back and forth at
a frequency of about .1 Hz.
What is the period of vibration?
Speed Review
an object’s speed is described by the distance traveled
in a specific amount of time (generally measured in
m/s)
Wave Speed
v = λ ● f
wave speed = wavelength ● frequency
Lambda
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