Ch 15 Traveling Waves and Sounds
how can you compare the intensities between two sources? (formula)
(I₁/I₂)=(R₂²/R₁²)
describe why the block attached to a spring vertically shows an harmonic motion?
--the mass has an equilibrium position at which the net force is zero -If the mass is displaced from equillibrium, a linear restoring force causes the mass to undergo simple harmonic motion
ciruclar wave (what it is, how looks, and what are its wave fronts)
-2-dimensional wave that spreads across a surface -it looks like circles within circles -wave fronts are circles
amplitude (symbol and definition)
-A -maximum value of displacement of the wave from mid line
As wave passes through a medium what happens to atoms? this is _of the medium
-As a wave passes through a medium, the atoms that make up the medium are displaced from equilibrium -disturbance of the medium
what properties of the string determine the speed of waves traveling along a string? (include formula )
-Because the pulse does not travel faster on a longer and thus more massive string, neither the total mass nor the total length L is important -The speed depends on the mass-to-length ration, which is called the linear density (µ) of the spring -µ=m/L
surface water waves result from_and particle motion is _
-Combination of both -Particle motion = circular
why if you increase temperature, you increase sound speed?
-If increase temperature of air, you will have oscillation more high and violent -so speed will increase
which solid would have a higher spread of speed: metal or nonmetal?
-In solids, the metals have a higher speed than nonmetals -because of structure -the stronger the bond, the distance between molecules will be closer and is so hard to break, so it will have a higher speed
what is the period?(2) (include symbol)
-T -is the time interval to complete one cycle of the motion -is the time between successive crests
Longitudinal waves (what are them, how particles move, example (2))
-Vibration direction parallel to wave propagation direction -the particles in the medium move parallel to the direction in which the wave travels -Particles in medium move closer together/farther apart -Example: sound waves -If you have a chain of masses connected by springs, you give the first mass in the chain a sharp push, a disturbance travels down the chain by compressing and expanding the spring
transverse waves (what are them and example)
-Vibration direction perpendicular to wave propagation direction (particles in the medium move perpendicular to the direction on which the wave travels) -Shaking the end of a stretched spring up and down creates a wave travels along string in a horizontal direction while the while the particles that make up the string oscillate vertically Example: plucked string
How does the speed of a wave on a string vary with the tension and the linear density? (2)
-Wave speed increases with increasing tension: a string with a greater tension responds more rapidly, so the wave will move at a higher speed. -Wave speed decreases with increasing linear density: A string with a greater linear density has more inertia. It will respond less rapidly, so the wave will move at a lower speed
describe how a history graph works [include type of wave of the example]
-We place a dot at a particular point on the string carrying the wave -as the wave travels horizontally, the dot moves vertically; this is a transverse wave -we can use this information form these graphs to construct a graph that shows the motion of this one point on the string as time passes
In transverse waves, while the wave propagates in_motion, the particles will_. Both are_to each other
-While wave propagates in horizontal motion, the particles move up and down -perpendicular
the position vs time graph of sinusoidal motion is_. (include formula)
-a cosine curve -x(t)=Acos((2πt)/T) position x as function of time t
we need a function that tells us _ (about the wave (2)) a function that depends on_(2)
-a function that tells us what a wave is doing at an instant of time (when) at a particular point in space (where) -We need a function that depends on both position and time
describe snapshot graph
-a graph that shows the wave's displacement as a function of position at a single instant of time -The graph shows the wave's displacement y at a particular instant of time t₁ as a function of position x along the string -This is a "snapshot" of the wave, much lke what you might make with a camera whose shutter is opened briefly at t₁ -picture of the wave at the instant
what is a difference between a particle and a wave regarding location?
-a particle is in one place at at time, but a wave is not localized -a wave is spread out though space at each instant of time
what kind of wave is sound wave? explain why and compare with previous example
-a sound wave is a longitudinal wave -when the cone of the loudspeaker moves forward, it compresses the air in front of it -The compression is the disturbance that travels forward through the air -This is much like the sharp push on the end of the chain of springs
the wave model is based on the idea of a_
-a traveling wave
what is transferred in a wave? what is not trasferred?
-a wave transfers energy, but there is not material or substance transferred
sound waves can travel though_mediums (4)
-air -gas -liquids -solids
at what speed electromagnetic waves travel?
-all electromagnetic waves travel at the same speed in vacuum -we call this speed speed of light
what are the 3 characteristics of a wave?
-amplitude -wavelength -frequency
traveling wave
-an organized disturbance traveling at a well-defined wave speed v
why speed at liquids is higher than at gas? how this compares in solids?
-because particles are closer -so when one particle pushes another, they propagate in a faster way -If very loose, like in the gas, the particles are separated between each other and will travel slower -Smaller molecule distance, you will have a higher speed of sound waves -which are longitudinal waves -Highest speed at solids -Speed at solids is quicker than in liquids -quicker to push the next molecules
Why you do not have sound at space?
-because there is no particles to move -sound needs a medium to travel
if x is a sinusoidal function, then x is (2 limits)
-bounded: it can take only values between A and -A -periodic: it repeat the same sequence of values over and over again. whatever value x has at time t, it has the same value at t+T
what are the way in which a wave can spread? (3)
-circular wave -spherical wave -plane wave
what part of the sinusoidal wave is the compression of sound? rarefractions?
-compressions: crest -rarefractions: trough
which bond is the strongest?
-covalent bond is the strongest
wave fronts are _of the wave. they are spaced _apart
-crest -one wavelength
a wavelength can be the distance between two consecutive_
-crests -troughs
electromagnetic waves can travel through_(medium)
-do not need material medium and can travel through vacuum
a light wave is what type of wave? it is part of _
-electromagnetic wave -it is an oscillation of the electromagnetic field
a traveling wave transfers_from_to_
-energy -one point to another point
as wave spreads out, so does_.what happens to intensity?
-energy of the wave -intensity decreases
what are the ranges of wavelength of visible light?
-from 400nm to 700nm
echolocation (what kind of frequency needed, what it is, what animals use it)
-high frequency sounds are needed for this -emitting a pulse of sound and listening for its reflection -bats perform it to find its prey
how a loudspeaker creates sound? (include type of motion, and name of regions that this motion creates (2))
-if the loudspeaker cone moves with simple harmonic motion (back and forth), it will create a sinusoidal sound wave -each time the cone moves forward, it moves the air molecules closer together, creating a region of higher pressure -a half cycle, later as the come moves backward, the air has room to expand and the pressure decreases -these regions of higher and lower pressure are called compressions and rarefactions
You can increase the wave speed by_the string's tension (make it_)or by _the string's linear density (make it_)
-increasing -tighter -decreasing -skinnier
You ears are sensitive to sounds over a remarkable range of _, so we use the _for sound intensity level
-intensities -logarithmic decibel scale
intensity is what kind of ratio? when is higher its value?
-intensity is a power-to-area ratio -a wave focused onto a small area has a higher intensity than a wave of equal power that is spread out over a large area
history graph
-is a graph of the displacement of one point in a medium vs time
what kind of graph is the velocity graph? include formula
-is an upside down sine function with the same period T -vx(t)=-vmax sin(2πt/T)=-vmax sin (2πƒt) the minus is to turn the sine function upside down
how the intensity is affected as you go farther away from the source? why? (2)
-it becomes less intense as you get farther away from the source -because spherical waves spread out to fill larger and larger volumes of space -To conserve energy, the wave's amplitude must decrease with increasing distance r
how acceleration vs time looks? (include formula)
-it looks to be inverted form of the position-vs-time graph -the acceleration vs time graph in the table is clearly an upside-down cosine function with the same period T -ax(t)=-amax cos (2πt/T)= -amax cos(2πƒt)
plane wave
-it you observe a spherical wave very far from its source, the small piece of the wave front that you can see is a little patch on the surface of a very large sphere -If the radius of the sphere is sufficiently large, you will notice the curvature and this little patch of the wave front appears to be a plane -this idea is called plane wave
the speed of sound in a solid depends on_(2) (include what solid transmits the highest speed of sound and why, and a low speed solid material)
-its density and stiffness -light, stiff solids (such diamond) transmit sound at very high speeds -the sound speed is much lower in dense, soft solids such as lead
a fat string has a value of linear density than a skinny string made of the same material. Similarly, a steel wire has a _of linear density than a plastic string of the same diameter
-larger value of µ -larger value of µ
electromagnetic waves, such as_, travel at a much _ speed than do mechanical waves
-light -higher speed
For mechanical waves, the terms of transverse and longitudinal waves describe the relationship between_
-motion of particles tha carry the wave and the motion of the wave itself
each point in the medium _(how move in a wave)
-oscillates with simple harmonic motion as the wave passes
once a wave distribution is created by the source, the disturbance travels_(direction) through the medium at _
-outward -wave speed (v)
In transverse wave (how particles move vs wave move)
-particles of the medium move perpendicular to the direction in which the wave travels
what can you determine in a history graph? why?
-period -because x-axis is time (seconds)
what characteristics of the motion are sinusoidal graphs? (3) how is their shape?
-position -velocity -acceleration -the graphs have same general shape
acceleration is proportional to_, but with _
-position -with a minus sign
the speed of sound does not depend on_(2)
-pressure -density of the gas
quantities such as brightness or loudness depend not only on the_, but also on the_
-rate of energy transfer, or power, but also on the area that receives that power
for diagnostic purposes, X-rays are used for_and ultrasound is used for_. type of wavelength and why?
-see images of bones -creating images of soft tissues -this are short wavelengths needed for fine details
at one instant, the wave is a _function of the _along the wave, with a _. [include formula]
-sinusoidal -distance x -wavelength λ y(x)=A cos (2π(x/λ))
how the circular waves would look very far away from the source?
-small sections of the wave fronts appear to be straight lines
what are the 2 graphs that we can use for waves?
-snapshot graph -history graph
In which phases sound travels faster? (liquid, gas, solid)
-sound waves travel faster in liquids than in gases, and faster in solids than in liquids
light can travel through_, but_cannot
-space -sound
Y function of x (Y(x)) my _ is fixed and the graph will have the _ (how look)
-t (time) -shape of the actual wave
what two points of the wave have amplitudes?
-the crests of the wave--the high points--have displacement ycrest=A -the troughs--the low points--have displacement ytrough=-A
how is compared putting light on a wall directly vs with a mirror focusing it into a smaller area? (2)
-the energy emitted by the bulb is the same in both cases, but the light is much brighter when focused onto a small area
what is the relation between frequency and amplitude? what is a consequence of this?
-the frequency does not depend on the amplitude of the motion -small oscillations and large oscillations have the same period
wave fronts (include how they are spaced one after the other one)
-the lines that locate the crests in circular wave -they are spaced precisely one wavelength apart
In an oscillating motion, when does the maximum speed happen?
-the maximum speed occurs when the mass passes through its equilibrium position -in a graph, it is when the wave intersects with the x-axis of position
example of mechanical waves (3)
-the medium of water wave is water -the medium of sound wave is air -the medium of stretched string is the string
by looking a graphs with waves of the same speed, which one would have the greatest frequency?
-the one that has the shortest wavelength -the one with the crest closest together
In longitudinal waves (how particles move vs wave move?)
-the particles of the medium move parallel to the direction in which the waves travels
the wave speed does not depend on_(4)
-the shape or size of the pulse, how the pulse was generated, on how far it has traveled
a way to remember the sign of the wave in the formula is_
-the sign is opposite the direction of travel -wave moving to the right (+xdirection) has a - in the expression -a wave moving to the left (the -direction) has a +
what properties of a gas determine the speed of a sound wave traveling through the gas? (3)
-the speed of a sound pulse is related to the speed with which the molecules of the gas move-->faster molecules mean a faster sound wave -temperature -molecular mass
At a given temperature, how molecular mass of the gas relates to the speed of sound? (include example of who is faster helium or simple air)
-the speed of sound increases as the molecular mass of the gas decreases -ex: the speed of sound in a room-temperature helium is faster than that in room-temperature air
the motion of a pulse along a string is a direct consequence of _. An external force may have been required to create the pulse, but once started, the pulse_
-the tension action on the segments of the string -continues to move because of the internal dynamics of the medium
what moves when a mechanical wave travels through a medium? why?
-the wave itself does not move, the particles that make up the medium move -The wave itself is not a particle, so we cannot apply Newton's laws to the wave. However, we can use Newton's laws to examine how the medium responds to a disturbance
what is the relationship between wavelength and frequency?
-they are inversely proportional -the larger the wavelength, the smaller the frequency -the shorter the wavelength, the larger the frequency
the disturbance propagates through the medium, and a wave does_but the medium as a whole _. Explain how this applies to the example of water waves. How this applies to particles in a string?
-transfer energy -does not travel -the ripples of the pond (the disturbance) move outward from the splash of the rock, but there is no outward flow of water -the particles of the string oscillate up and down but do not move in the direction of a pulse traveling along the string
what are 2 types of waves?
-transverse -longitudinal
a wave on a string is a_. why?
-transverse wave -As a pulse approaches from the left, the string near the little dot begins to curve -Once the string curves, the tension forces pulling on a small segment of string no longer cancel each other -As the wave passes, the curvature of the string leads to a net force that first pulls each little piece of the string up and then, after the pulse passes, back down -Each point of the string moves perpendicular to the motion of the to the motion of the wave
electromagnetic wave is what kind of wave? why?
-transverse wave -because B field is perpendicular to the E field and they are perpendicular to the propagation
all electromagnetic waves, regardless of wavelength and frequency, travel through_at_
-vacuum (or air) -with the same speed, which is c=3.00X10⁸m/s
list examples of electromagnetic waves (4)
-visible light -radio waves -microwaves -x-rays
what is the value of speed of light in vacuum?
-vlight=c=3.00X10⁸m/s
the _propagates but the _ of the medium don't
-wave -particles
the period is related to_. how?
-wave frequency -T=1/ƒ
we will introduce the basic properties of waves with a_that emphasize those aspects of_
-wave model -wave behavior common to all waves
list properties of wave (3)
-wave speed -wavelength -frequency
what can you determine in a snapshot graph? why?
-wavelength -because x axis is x (distance)
what is the relation of wavelength with energy? frequency with energy?
-wavelength is inversely proportional to energy. Meaning that the larger the wavelength, the lower the energy the wavelength will carry -frequency is directly proportional to energy. The larger the frequency, the more energy the wave carries
how wavelength relates to period?
-wavelength is the spatial analog of period -period is the time in which the disturbance at a single point in space repeats itself -The wavelength is the distance in which the disturbance at one instant of time repeats itself
spherical waves
-waves that move in 3 dimensions
why the projection of circular motion is simple harmonic motion?
-we can locate the particle by the angle θ measured counterclockwise from the x-axis -projecting the ball's shadow onto a screen is a equivalent to observing just the x-component of the particle's motion
how can you hear?
-when the wave reaches your ear, the oscillating pressure causes your eardrums to vibrate -this vibration is transferred through your inner ear to the cochlea, where it is sensed
traveling wave
-which is an organized disturbance that travels with a well-defined wave speed
Y function of t (Y(t)) m_- is fixed, _(how do you get this graph?)
-x (position) -you set a point and see how it varies, that will be graph
A quantity that oscillates with time can be written in the following two graphs_.how is it called? how both graphs compare?
-x=Asin((2πt)/T) -x=Acos((2πt)T) -is called a sinusoidal function with period T -the graphs of both functions have the same shape, but they have different initial values t=0s (sine is at 0 and cosine is at A)
what are the axis of the history graph?
-y axis is y (motion of one point at y (m) -x axis is time (seconds)
what are the y and x axis of the snapshot graph?
-y is y -x is x shows wave motion at that instant of time in the y and x axis
wavelength (symbol and definition (2))
-λ -the distance spanned by one cycle of the motion -the distance between two equal consecutive parts of the wave
list in order of greatest wavelength to shortest wavelength the 8 electromagnetic waves
1. AM radio 2. FM radio 3. Microwaves 4. Infrared 5. Visible light 6. Ultraviolet light 7. X-rays 8. Gamma rays
what a sequence of snapshot graphs can tell you about the wave motion? (2)
1. the wave moves without changing shape 2. the wave moves forward ∆x=v∆t during time interval ∆t
what is the range of hearing for a human?
20Hz to 20,000Hz
what is the speed of air at 20⁰C?
343 m/s
describe the harmonic motion of a ball that is hanging vertically from a spring (9)
A mass is suspended from a vertical spring with an equilibrium position at y=0. The mass is then lifted upward by a distance A and released. We measure the position with respect to equilibrium position, negative below 1. the mass starts at its maximum positive displacement y=A. the velocity is zero at the instant the mass is released, but the acceleration is negative because there is a net downward force 2. The mass is no moving downward, so the velocity is negative and the distance form the equilibrium is decreasing. As the mass nears equilibrium, the restoring force, and thus the magnitude of the acceleration decreases 3. at this time the mass is at equilibrium position, so the net force and thus the acceleration is zero. the speed is at a maximum, but the velocity is negative because the motion is downward 4. the velocity is still negative but its magnitude is decreasing, so the acceleration is positive 5. at this time, the mass has reached the lowest point of its motion, with y=-A. This is a turning point of the motion. The velocity is zero. the spring is at its maximum extension, so there is a net upward force and the acceleration is positive 6. the mass has begin moving upward; the velocity is positive, and the acceleration is positive 7. the mass is passing through the equilibrium position again, but in the opposite direction. the acceleration is zero because there is no net force; the upward velocity is positive 8. the mass continues moving upward. the velocity is positive bit its magnitude is decreasing, so the acceleration is negative 9. the mass is now back at its starting position. This is another turning point; the mass is at rest but will soon begin moving downward, and the whole cycle will repeat
Suppose you shake the end of a stretched string to produce a wave. which of the following actions would increase the speed of the wave down the string? There may be more than one correct answer; if so give, give all that are correct a. move your hand up and down more quickly as you generate the wave b. move your hand up and down a greater distance as you generate the wave c. use a heavier string of the same length, under the same tension d. use a lightehr string of the same length, under the same tension e. stretch the string tighter to increase tension d. loosen the string to decrease tension
D and E Shaking your hand faster or father will change the shape of the wave, but this will no change the wave speed; the speed property of the medium. Changing the linear density of the string or its tension will change the wave speed. To increase the speed, you must decrease the linear density or increase the tension
energy is high at_and low at_
Energy is high at higher frequency and lower wavelength
gases and liquid support what kind of waves?
Gases and liquids - support only longitudinal waves
If we have x at the x axis, means what I am looking at? (in terms of waves)
I am looking at the shape of the wave taken at an instant time (snapshot graph)
what is the formula that defines the intensity of the wave?
I=P/a
light wave is_(type and shape)wave at_speed
Light wave is transverse wave and sinusoidal at light speed
sound waves are what kind of wave? why?
Sound waves are longitudinal wave because of air particles, which will be moving be back and forth and parallel in direction with the displacement
what is the symbol for period of oxcillation?
T
what is the SI unit of intensity?
W/m²
what is another way to write the formula in terms of frequency?
X(t)=Acos(2πƒt)
what is the relation between amplitude and speed?
a large amplitude implies a high speed because you move a large distance
snapshot graph
a picture of a wave at one instant in time
what is the relation between period and speed?
a small period implies a high speed as well because the object must complete its motion in a short time
a wave disturbance is created by_
a source
sinusoidal waves are made by_
a source moving with simple harmonic motion
sinusoidal wave is the type of wave produced by_
a source that oscillates with simple harmonic motion
sound wave is_
a wave of compressions and rarefractions of a medium such as air
what is the rule regarding mechanical waves?
a wave transfers energy, but it does not transfer any material or substance outward from the source
special value of a. x=Asin((2πt)/T) b. x=Acos((2πt)T) at t=3/4 T
a. -A b. 0
special value of a. x=Asin((2πt)/T) b. x=Acos((2πt)T) at t= 1/2 T
a. 0 b. -A
special value of a. x=Asin((2πt)/T) b. x=Acos((2πt)T) at t=0
a. 0 b. A
special value of a. x=Asin((2πt)/T) b. x=Acos((2πt)T) at t=T
a. 0 b. A
special value of a. x=Asin((2πt)/T) b. x=Acos((2πt)T) at t=1/4 T
a. A b. 0
A plane wave, a circular wave, and a spherical wave all have the same intensity. Each of the waves travels at the same distance. Afterward, which have has the highest intensity? why? A. a plane wave B. a circular wave C. a spherical wave
a. plane wave the plane wave does not spread out, so its intesity will be contains. The other two waves spread out, so their intensity will decrease
what is the formula of maximum acceleration in a ciruclar motion?
amax=(2πƒ)²A
what do you need to know at least to know everything about simple harmonic motion? (2)
amplitude and frequency
mechanical waves
are waves that inovle the portion of a substance through which they move, the medium
what is the x-component of the acceleration of a ball in circular motion?
ax=-acosθ=-(2πƒ)²Acos(2πƒt)
why we have different colors?
because each color has a respective wavelength
how can we increase sunlight intensity?
by using a lens to focus sunlight onto a small area, increasing the intensity
how do we represent the speed of light?
c
both_motion and_motion are motions that repeat
circular motion simple harmonic motion
the spreading of water waves is what kind of wave?
circular wave
the wave moves at what speed?
constant speed
wavelength
distance between successive wave crests
visble spectrum is part of _
electromagnetic spectrum
what are two types of waves that do not require a medium?
electromagnetic waves matter waves
all waves carry_
energy
the inverse-square dependence of r is really just a statement of_
energy conservation
how power changes in a spherical wave?
for a spherical wave the power decreases with the surface area of the spherical wave fronts
ultrasound (Include frequency)
frequencies that are well above our range of hearing, which we cannot hear anymore -above 20,000 Hz
what arises when you move a block out of its equilibrium state, which is connected to a spring?
harmonic motion
unit of frequency
hertz Hz
graphing the motion of one point in the medium gives a_
history graph
the wave speed
how fast does the wave move
frequency
how many waves streak a point of reference each minute
intensity
how much energy does a wave carry
shorter wavelengths in visible light are seen as_and measure_
in the 400-500nm range, are seen as blue or violet light
longer wavelengths in visible light are seen as_and mreasure_
in the 600-700nm range, are seen as orange or red light
we would say that the focused light is more_than the diffuse light that goes in all directions
intense
Wave
is a disturbance traveling trough a medium
intensity
is the ratio of the power to the area
what a history graph shows?
it shows the history (the time evolution) of the particular point in the medium that we chose
mechanical waves require a_
material medium
what is one of the most significant discoveries of the 20th century regarding atoms and electrons?
material particles, like atoms and electrons, have wave-like characteristics
mechanical waves require a_
medium
we use a history graph when we want to consider the motion of_
medium
does the history graph would look the same as the snapshot graph?
no
during the time interval of exactly one period T, each crest of a sinusoidal wave travels forward a distance of exactly _
one wavelength λ
the circular wave fronts move_
outward from the source at a speed v
In a sinusoidal graph where y as a function of time, we can read_
period
the motion of the wave is_
periodic
sound wave can also be considered a_wave
pressure wave
the speed of the wave is a property of_
property of the medium, not the wave
when you calculate the cosine of the wave functions, your calculator needs to be at_
radians
the history graph is not a picture of the wave, it is a_
record of teh motion of one point in the medium
compression
region of high pressure created by a loudspeaker as it moves forward
rarefraction
region of low pressure created by a loudspeaker as it moves backward
period unit is
seconds
in every problem dealing with graphs, especially sinuoidal graphs, always be careful to _
see axis! Look if x axis is time or x- position
what kind of wavelength of light is used for smaller details?
short wavelengths
the description of a wave motion is closely related to that of _(type motion)
simple harmonic motion
the x-component of a particle in uniform circular motion is_
simple harmonic motion
what is the mathematical description of a wave motion?
sinusoidal wave
the speed does not depend on_(2)
size or shape of the wave
what are two important waves?
sound light
what are examples of spherical waves? (2)
sound waves and light waves
solids support what kind of waves?
support both longitudinal and transverse waves
the speed of sound of air (and other gases) increases with_
temperature
how the bonds between atoms relate to the speed of sound?
the bonds between atoms in liquids and solids result in higher sound speeds in these phases of matter
what is the wave form of spherical waves?
the crests of the wave form a seris of concentric, spherical shells separated by the wavelength λ
y (x,t) means that_
the displacement y is a function of the two variables x and t
what animal has the most sensible hearing?
the elephant with <5Hz
Doppler effect
the frequency and wavelength are shifted when there is relative motion between the source and the observer of waves. We call this the doppler effect
in one period, the graph has moved _(in terms of wavelength)
the graph has moved by one wavelength
wave speed is a property of_
the medium
a snapshot graph shows what about the wave?
the motion of the wave
If a source of spherical waves radiates uniformly in all directions, what is the formula for power?
the power at distance r is spread uniformly over the surface a sphere of radius r. the surface area of a sphere is 4πr², so the intensity of a uniform spherical wave is I=Psource/4πr²
the how the pressure shows in a snapshot graph due to the motion of the loudspeaker?
the pressure oscillates sinusoidally around teh atmospheric pressure patmos
the motion of the waves depends on_
the properties of the medium
what is the power of a wave?
the rate, in joules per second, at which the wave transfers energy (unit=watts)
as the wave moves to the right, how its shape changes?
the shape stays the same
for a wave on a string, what is the medium?
the string
what electromagnetic waves does not require vs mechanical waves do?
they do not require a medium
what is fixed in a graph in which y appears in y axis and x appears on x axis?
time is fiex
as time passes, what is the direction of the wave in consecutive snapshot graphs?
to the right
spectators at a sporting event do the wave. Is this a transverse or a longitudinal wave?
transverse. the wave moves horizontally through the crowd, but individual spectators move up and down, transverse to the motion of the wave
the wave model is built around the idea of _
traveling wave
linear density characterize the _
type of string you are using
if go above visible light, you have_
ultraviolet light
what is the relation between uniform circular motion and harmonic motion?
uniform circular motion projected onto one dimension is simple harmonic motion
what is the formula for the particle in a circular motion? what is the x-component velocity formula of this motion?
v=2πfA Vx=-Vsinθ=-(2πƒ)Asin(2πƒt)
what is the wave speed formula?
v=distance/time=λ/T v=ƒλ
what is the formula for maximum speed in ciruclar motion ?
vmax=2πƒA=(2πA)/T
what is the velocity formula that includes amplitude?
vmax=2πƒA=(2πA)/T
what is the formula that describes the motion of the string, which is an expression for the speed of a wave?
vstring=√(Ts/µ) vstring=wave speed Ts=string tension linear density=µ
In a sinusoidal graph where y as a function of x (position), we can read _
wavelength
electromagnetic waves
waves of electromagnetic field
what is fixed in a graph in which y appears in y axis and t appears in x axis?
x is fixed
express the x-component of the particle with angular velocity
x(t)=Acos(2πƒt)
state the 3 formulas used for simple harmonic motion: (for position, velocity, and acceleration)
x(t)=Acos(2πƒt) v(t)=-(2πƒ)Asin(2πƒt) a(t)=-(2πƒ)²Acos(2πƒt)
the _of the particle position in a circular motion describes the position of the ball at harmonic motion
x-component
what is the formula to get the x-component of the particle moving in circular motion
x=Acosθ
what is the function that describes the wave displacement as a function of time at one point in space? what is the function that describes the wave displacement as a function of position at one instant in time? how can you combine them?
y(t)=A cos(2ππ(t/T)) y(x)=A cos (2π(x/λ)) y(x,t)=A cos (2π((x/λ)-(t/T))) [it tells displacement of traveling wave moving to the right with amplitude, wavelength, and period]
for a wave traveling to the left, what is the formula?
y(x,t)=A cos(2π((x/λ)+(t/T))
even if the oscillation begins at a different positon, it will certainly pass through_
y=A
If the particle starts at zero angle, what would be the formula to determine angle at a later time? (include formula of angular velocity)
θ=wt where w is the particle's angular velocity w=2πƒ
the wave moves forward at a distance_(formula)
∆x=v∆t during each time interval ∆t
