Mcat - Math And Physics Ch. 7

Front 1

Transverse Wave

Back 1

- particles are oscillating perpendicular to the direction of energy transfer

Front 2

Longitudinal Waves

Back 2

- particles of the wave oscillate parallel to the direction of propagation (direction of energy transfer)

Front 3

Frequency

Back 3

- number of wavelengths passing a fixed point per second (hertz)

Front 4

Propagation (movement) Speed (v)

Back 4

v= (freq)(wavelength)

Front 5

Period

Back 5

- number of seconds per cycle

T = 1/freq

Front 6

Angular Frequency

Back 6

- used in simple harmonic motion in springs and pendula

w= 2(pi)(freq)

Front 7

Principle of Super Position

Back 7

-Resultant of 2 waves in phase: amplitude = sum of the 2 amplitudes (constructive interference)

- Resultant of 2 waves out of phase: amplitude = difference of the 2 amplitudes (destructive interference)

Front 8

Standing waves

Back 8

- 2 points are fixed and frequencies will create a wave that seems to be stationary (incident wave and reflected wave are out of phase 180°)

Front 9

Node

Back 9

- points in a wave that remain at rest (where amplitude is constantly zero)

Front 10

antinodes

Back 10

- points midway between nodes that fluctuate with amplitude

Front 11

timbre

Back 11

- quality of sound

Front 12

noise

Back 12

- vibration of a single frequency that an object creates when hit (pencil, crumbled paper, other solid objects)

Front 13

Resonating system

Back 13

- frequency of the periodic force is equal to the natural frequency of the system

- amp of oscillation is at a maximum

Front 14

damping

Back 14

-"attenuation"

- decrease in amp of a wave caused by an applied or non-conservative force

Front 15

Sound

Back 15

- longitudinal wave transmitted by oscillation of particles in a deformable medium

- v = sqrt(B/density)

B = bulk modulus (measure of a mediums resistance to compression)

Front 16

Pitch

Back 16

- perception of the frequency of sound

- lower freq = lower pitch

Front 17

Sound wave frequencies to the human ear

Back 17

- less than 20 Hz = infransonic waves

- greater than 20,000 Hz = ultrasonic waves

Front 18

Doppler Effect

Back 18

- difference btwn actual frequency and perceived frequency when the source of the sound and the sound detector are moving relative to one another

- Example: ambulance sirens

Front 19

Doppler Effect Equation

Back 19

-fo=fs v(+-) vo/v(+-)vs
fo=observed frequence
fs=frequency by source
v=speed of wave
vo=speed of the observer
vs=speed of the source

- + = moving towards

- - = moving away

Front 20

Shock wave

Back 20

- highly condensed wave

- can cause physical disturbances as it passes through other objects

- max impact when source is traveling at the speed of sound

Front 21

Sound intensity

Back 21

-avg rate of energy transfer per area across a surface perpendicular to a wave

-**Power transported per unit area**-

-proportional to the sqr of the amplitude

- INVERSELY proportional to the sqr of the distance

I = P/a (Watt/m^2)

Front 22

Eqn relating wavelength and length of a string

- and with freq -

Back 22

wavelength = 2L/n

- n = harmonic

Freq = nv/2L

v = wave speed

Front 23

Wavelength/freq of a closed pipe

Back 23

- open end = antinode

- closed end = node

wavelength = 4L/n

-**N CAN ONLY BE ODD INTEGERS**-

freq = nv/4L

Front 24

Ultrasound

Back 24

- uses high freq sound waves (outside human range) to compare relative densities of tissues in the body

Front 25

Doppler unltrasound

Back 25

- to determine flow of blood by detecting a freq shift associated with the movement toward or away from the receiver