WAVES AND PERIODIC MOTION Flashcards
What is a wave
transfer of energy and momentum from one point to another
what does a wave transfer
energy and momentum
what happens during energy transfer
each particle in the medium vibrates in
simple harmonic motion respectively to an equilibrium point
what are the two types of wave
mechanical and electromagnetic
what are the two types of mechanical wave
transverse and longitudinal
what is a transverse wave
wave that causes the medium to be displaced perpendicularly to the
direction the wave is traveling
what is a longitudinal wave
a wave that causes the medium to be displaced parallel to the
the direction the wave is traveling
example of transverse waves
waves on a guitar string are transverse
waves
example of longitudinal waves
waves from sound are longitudinal waves
what is wavelength
measured from any point in the wave to the point where the wave begins to repeat itself.
what is frequency
the number of wavelengths that pass a single fixed point in one second
what is wavelength measured in
metres
what is frequency measured in
Hz
how do you calculate the velocity of a wave
velocity = f x wavelength
what is amplitude
maximum displacement of a particle from its equilibrium point
what is intensity
square of amplitude
what is amplitude always gonna be
positive
what is a period
number of seconds it takes for one wavelength to pass a fixed point.
what is the mathematical property of a period
reciprocal of frequency
how do you calculate a period
T = 1/f
what is the easiest way to measure wavelenth
from crest to crest or trough to trough of a transverse wave
what is a wave’s distance from the x axis representing
distance from the source
what is a wave’s distance from the y axis representing
displacement/elevation
what is ‘in phase’ waves
two waves begin at the same point and have the same wavelength
what happens when two transverse waves share the same space
displacements add together at each point along to wave
what is interference
superposition of waves > new wave
what are the two types of interference
constructive and destructive
what is constructive interference
waves add together to create a wave with a larger displacement than either original wave
what is destructive interference
waves add together to create a wave with a smaller displacement than either original wave
what happens in constructive interference
wave peak comes upon wave peak causing amplification
what happens in destructive interference
wave peak comes upon wave trough causing extinction
what happens when a series of waves hit an object
cause vibrations within the object
what happens if the object itself vibrates due to the wave hitting on the object
If the series of waves cause an object to vibrate at one of its natural frequencies, this phenomenon is termed resonance
when does resonance only occur
only occurs when the first object is vibrating at the natural frequency of the second object.
how are standing waves produced
from the repeated interference of two waves of identical frequency moving in opposite directions along the same medium
what is the structural composition of standing waves
All standing waves consist of nodes and antinodes
what do nodes on a graph look like
nodes are amplitude 0
anti nodes are maximum amplitude points
what does nodes result from
the destructive interference of the two waves and are therefore points of no displacement
what does antinodes result from
from the constructive interference of the two waves and therefore undergo maximum displacement from the rest position
amplitude can also be seen as what motion property
displacement
no amplitude suggests
no displacement
what is a harmonic series
list of the wavelengths from largest to smallest of the possible standing waves
how are harmonics numbered
from the longest to shortest wavelength
what does the first harmonic contain
fewest number of nodes, which is two (frequency N)
what does the second harmonic contain
has one more node than the first harmonic
4 nodes
(frequency 2N)
how does each successive harmonic vary from it’s previous one
one more node from before
how would we calculate the frequency of the 5th harmonic
3 x N
what is periodic motion
Motion that is regular and repeating
contextualise periodic motion to most objects
Most objects that vibrate do so in a regular and repeated fashion, and thus their vibrations are periodic
how must the vibrations be within an object for it to be considered periodic motion
vibrate in a regular and repeated fashion
