Term

Definition
SHM. certain type of periodic motion that occurs as a result of linear restoring force. Graphically looks like a cosine or sine depending on the starting position of the object t=0 on position (y) and time (x) axis. When a solid object moves in SHM it creates a frequency. 


Term

Definition
Specific type of push or pull: 1. The force is in the opposite direction of the displacement from the equilibrium. 2. the force is proportional to the distance from the equilibrium position 


Term

Definition
the maximum distance from the equilibrium position. Graphically it is the distance from the top of the the curve to horizontal, or the bottom to horizantal.
The amplitude can be the maximum value of any quantity of interst such as speed, (or velocity), change in pressure, change in density. always same on both sides of equilibrium. Cosine always starts at the top of a graph, (0). amplitude = A 


Term

Definition
The amount of time it takes for an object to move back and forth once. grahically it is the amount of time it takes in order to draw a repeating shape once. time it takes for one oscillation. unit = seconds. one oscillation is from one peak to next peak (distance). period = T. T= 1/F 


Term

Definition
the number of times an object oscillates i one second. unit = hertz (Hz). frequency = f. f=1/T 


Term

Definition
when the period is lower that means the frequency is higher. and when the period is higher that means the frequency is lower. 


Term

Definition
angular frequnecy
W=2∏F
alwasy start with W when graphing the shape of an oscillation 


Term
Shape of an oscillation (cosine) 

Definition
x(t)= Acos(Wt+Φ) (equation when wave is in SHM)
t = time
Φ = angle phase 


Term

Definition
always x axis on a graph unit = t 


Term

Definition
An angle between 0 and 360 degrees that specifies a point in one cycle.
0 = beginning of cycle
90 = 1/4 from beginning
180 = 1/2
270 = 3/4
360 = same as 0 degrees
graphical equation = Sin(Wt) 


Term

Definition
180 degrees = half the period
cancels out sound waves
if two graphs are out of phase, they are the same shape and and everything, but flipped upside down. 


Term

Definition
2 quantities have the same period and frequncy and are not offset at all.
In phase means in sync waves. 


Term

Definition
Process by which waves appear to bend around corners
Ie. someone facing the opposite direction and the abilit to still hear them is because of diffraction. 


Term
Polarization (transverse) 

Definition
transverse wave: the object of the wave is moving in a perindicular manner relative to the direction the wave is traveling.
the object is moving up and down along an x axis.
if polarized; the object moves in a particular direction in the plane.
the motion is ordered.
if unpolarized; moves in all directions and is the motion is random. 


Term

Definition
constant vaue of force that is pulling or pushing the object in motion.



Term

Definition
F = K(x)
F = force
W =(√K/m)



Term

Definition
Velocity
velocity as a function of time:
V(t) = W^{2}ASin(Wt + Φ) 


Term

Definition
x(t)
position as a function of time:
x(t) = Acos(Wt + Φ) 


Term

Definition
(a) acceleration as a function of time:
a(t) = W^{2}Acos(Wt +Φ) 


Term

Definition
the material that carries the energy moves in a direction that is perpindicualr to to the energy itself.
particle speed = rate at which the energy goes up and down
Deep water waves, and light waves 


Term

Definition
the material that carries the energy is moving in a paralell direction compared to the direction of the energy itself.
sound waves.
molecules move from mouth to ear in a longitudinal manner. 


Term

Definition
speed of anything = distance/time
v = x/t
f= λ/T 


Term

Definition


Term

Definition
v(sound) = (331+.6T_{c })
unit = meters/second
if the air is hotter the wave moves faster, and vice versa if the air is colder.
(25 m/s = 60 mph) 


Term

Definition
345 m/s
use this assumption when speed and temperature are not given 


Term

Definition


Term
largest and smallest wavelengths that can be heard? 

Definition
345 m/s
20 Hz
= 17.5 meters = maximum wavelength
345 m/s
20,000 Hz
= 17.25 mm = 1.725 cm = minimum
(10 mm = 1 cm) 


Term
Huyugens principle (H's principle) 

Definition
all parts of a wave act as sources of spherical waves in three dimensions
ie: old waves make new waves like the ripple effect on water. 


Term
Priciple of superposition 

Definition
to find the total amplitude of two or more waves, just add the individual amplitudes of each wave 


Term

Definition
if a wave spreads out in all directions (three dimensions) then its intensity will decrease in proportion to the square of the distance from its source.
ie: three dimension 5x the distance = intensity will decrease 25 times.
two dimensions the intensity will decrease in proportion to the distance
ie: 5x the distance = intensity will decrease by 5 


Term

Definition
reflection occurs when a wave bounces off of a boundry between two differnt materials.
Th angle of the incident = the angle of reflection
25 degree angle of incident = 25 degree angle of reflection 


Term

Definition
occurs when the wave changes direction due to crossing through a boundry betwen two different materials.
wave bends
light traveling through glass changes direction 


Term

Definition
when a wave begins to disperse through space and spread as it moves further and further.
the lower the frequency the higher the dispersion, and vice versa for higher frequency 


Term

Definition
waves don't necessarily interfere, they combine in two different manners having different effects



Term

Definition
when two or more waves with the same frequency fromm different sources combine at some point
when waves interfere spatially the resulting two extreemes are constructive and destructive 


Term
constructive spatial interference 

Definition
percents out of 100%
constructive = in phase
ie: 37% constructive/63% destructive
used for audio mixng 


Term

Definition
destructive spatial interference = out of phase
used for kareoke 


Term
constructive and destructive 

Definition
refers to the pressure change
constructive: two waves with same graphical patterns cmbine
results in increase in pressure change
destructive: two waves with opposite graphical pattersn combine and cancel eachother out.
pressure change is (wave one  wave two)



Term

Definition
occurs when two or more waves with different frequnecies from same source combine in some point in space. 


Term
Beats (time like interference) 

Definition
when waves interfere in time
two waves, different frequencies, same source, combine some point in space, two things could happen:
1. the frequency heard will be the average of the two frequencies:
f(average frequency of combined wave) =
f_{1} + f_{2}
2
2. the combined wave will get louder and softer at a rate equal to the absolute value of the of the difference between the two frequencies.
f(beat) = absolute (f_{1}f_{2})
(in tune frequency = 0) 


Term

Definition
if the source of the sound wave and/or the listener are moving with respect to the material carrying the sound wave, then the frequency heard by the listener will be different than the frequency emitted by the source
most commonly used to calculate speed of listener, or source.
effects the wavelength as well
f_{0} = V +/ V_{o}
V +/ V_{s}
do not compare the source ot the observer, compare it to the material carrying the wave. 


Term
doppler effect: approaching 

Definition
if the source and listener are moving toward eachother the frequency heard will be higher than the frequency emitted by the source.



Term
doppler effect: receeding 

Definition
if the source and and listener are moving away from eachother the frequency heard will be less than the source frequency. 


Term
doppler effect:
equations for different possibilities 

Definition
4 possibilities relative to material
1. S approaching, O approaching
= + numerator/ denominator
2. S approaching, O receeding
=  numerator/  denominator
3. S receeding, O receeding
=  numerator/+ denoinator
4. S receeding, O approaching
= + numerator/+denominator 


Term
Doppler effect:
material carrying wave is moving 

Definition
ie: air = wind speed
ie: source approaching moving 20 m/s
observer receeding moving 10 m/s
material moving 5 m/s toward
= source actually moving at 15 m/s
observer actually moving 5 m/s
material actually moving 0 m/s 


Term

Definition
shock waves occur when object is moving faster than the speed of sound
not periodic 


Term

Definition
created when multiple shock waves created at various times are combined to form one single shock wave of a large amplitude 


Term

Definition
sound waves that have a frequncy greater than 20,000 Hz
Sonar, medical imaging, material analysis, ultrasonic cleaning, dow whistles, echolocation, cavitation research 


Term

Definition
sound waves with frequency less than 20 Hz
cruisers with loud subwoofers, earthquakes, thunder, underground imaging (palentology, archeology, geology, natural resources), motion sickness. 


Term

Definition
one wave that travels in only one direction



Term

Definition
result of two identical waves traveling in opposite directions that undergo constructive spatial interference
often results from one wave that undergoes reflection at one or two places. 


Term

Definition
f = fundamental frequency
L = langth of string
F = force of tension apllied to the string
W = mass per unit length of string (density x area)
f = (1/2L)√(F/W)



Term
Mersennes law:
length, tension, mass per unit length 

Definition
1. length; longer strings produce lower notes; violin, viola, cello, bass
2. tension: greater tension creates higher notes; tuning a guitar or piano
(if increased from 5lbs to 10lbs, tension dos not double, watch for √)
3. mass per unit langth; thicker create lower notes; strings on a piano
(if you make a string 2x as thick, the area increase 4x, which = 1/2 the frequency) 


Term
Mersennes law; fundamental frequency 

Definition
equal to teh speed of the wave divided by twice the length of the string
(only applies to string/wire)
speed of a wave = √(F/W) 


Term
string instruments:
modes of excitation 

Definition
bowing; violin, viola, cello, etc. uses friiction, string stretches creating triangular displacment. Linear restoring force.
plucking; guitar, harp, harpschord, etc. spherical displacement
striking; piano, hammer dulcimer, etc. 


Term
wind instruments; open at one end and closed at other (closed) 

Definition
the air at the closed end cannot vibrate, and the air at the open end can.
creates a longitudal wave, molecules move towards open end of tube.
air at the open end always antinode (maximum amplitude)
clarinet, and bass clarinet



Term
wind instruments (closed): equations for wave length 

Definition
general equation = λ = (4L)/N
N = harmonic number, and is always odd



Term
wind instruments: open at both ends 

Definition
the air at bothe ends can vibrate.
string instruments work the same way
air molecules are moving like an accordian from the center of the tube; they move outward then inward after half a period.
base on node placement 


Term
open wind instrument equation 

Definition
f_{N} = (Nv)/(2L)
ie; 1 node λ = 2L
2 nodes λ = L
3 nodes λ = (2/3)L 


Term
standing wave relationship to nodes and harmonics 

Definition
1 standing wave = 1 node/1 harmonic
2 = 3 node/3 harmonic
3 = 5 node/5 harmonic 


Term
closed wind instruments and overtones 

Definition
1st node/harmonic = fundamental frequency
3rd node/harmonic= 1st overtone
5th = 2nd overtone
7th = 3rd overtone 


Term
wind instrument cylindrical open 

Definition
piccolos, flutes, and bass flutes
recorders 


Term
Wind instruments closed cylindrical 

Definition
clarinets and bass clarinets 


Term
wind instrument concical (not covered) 

Definition
soprnao, alto, tenor, bass sax
oboes, and bassoons
all brass instruments
acts like cylindrical open 


Term

Definition
organ pipes, flutes
mode of excitation 


Term

Definition
single or double
mode of excitation
single; clarinets and saxaphone
double oboes and bassons 


Term

Definition


Term

Definition
sinnging tubes or whirling tubes 


Term
how to change a note (frequency) (wind instruments) 

Definition
change the effective length
side holes; flute, clarinet, saxophone
valves; trumpet, tuba, french horn
slide; trombone, penny whistle 


Term
change the harmonic number (wind instruments) 

Definition
register keys; supresses fundamental to produce the next possible harmonic
over blowing; adds more energy to the air allowing for higher harmonics 


Term

Definition
related to the tone, note or pitch that is heard
larger freq. = higher notes, and vice versa for low freq. 


Term

Definition
related to the loudness that is heard
large amp = louder 


Term

Definition
the process in which energy of a SHM oscillator is transformed into some other kind of energy 


Term
Damped harmonic motion DHM 

Definition

