Waves (Etkina 20) Flashcards
the object that causes the vibration
source
short disturbance in surrounding medium
pulse
the moving circular disturbance created by the source on water
wave front
every point on the wave front has the same … at the same time
displacement from equilibrium
longitudinal wave: the vibrational motion of the particles/layers of the medium is … to the direction of propagation of the disturbance
parallel
transverse wave: the vibrational motion of the particles/layers of the medium is … to the direction of propagation of the disturbance
perpendicular
when a wave encounters any boundary between different media, some of the wave is
reflected back
sound is created by vibrations that cause … which travel through air from one place another
air pressure changes
sound waves are
longitudinal
period: … for one complete vibration of a … in the medium anywhere along the path
time period; point
frequency: the number of … per second of a … in the medium as the wave passes
vibrations; point
amplitude: the … of a … of the medium from its equilibrium position as the wave passes
maximum distance; point
speed: the distance a … travels during a …, divided by that time interval
disturbance; time interval
disturbance pattern of a wave repeats at a distance Tv, which separates neighboring locations on the wave that have the same displacement y and the same slope …
wavelength
y (x,t) =
y(x,t) = Acos[2T(t/T-x/ lambda)]
`2 points are in phase if at every clock reading their .. are exactly the same
displacements
2 points separated by a distance equal to an integer multiple of … are always in phase
wavelengths
the period and frequency of a wave depends on the
vibration source
wave speed depends on the … and the …
medium; type of wave (pulse)
… waves travel more slowly than … waves due to the types of … of the medium that occur when the waves propagate
transverse; longitudinal; deformation
the energy per unit circumference length and per unit time crossing a line perpendicular to the direction that the wave travels decreases as …, where r is the distance from the … of the wave
1/4; point source
the energy per unit area per unit time passing across the perpendicular to the direction that the wave travels decreases as …, where r is the distance from the point source of the wave
1/r^2
intensity of a wave is the energy per unit area per time interval that crosses perpendicular to an area in the medium through which it travels. I =
delta U/ delta t * A = P/A
reflected pulses are
inverted
When a thin rope is connected with a thicker rope, and an upright transverse pulse is transmitted, a … is initiated in the thick rope at the boundary. But since the thick rope has a larger mass per unit length, it exerts a … force, starting an … pulse back toward the left in the thin rope.
small amplitude upward pulse; downward; inverted reflected
When a thick rope is connected with a thinner rope, and an upright transverse pulse is transmitted, the small rope … its position relative to the thick rope and starts a small …pulse back in the thick rope due to its smaller mass per unit length.
overshoots; upright reflected
impedance: the degree to which waves are … and … at the boundary between different media
reflected; transmitted
impedance is the measure of the difficulty a wave has in … the medium, depends on the medium’s … and … properties
distorting; elastic; inelastic
If two media connected together have different elastic and inertial properties, wave traveling in one medium is partially …and partially … at the boundary. If the product of the elastic and inertial properties of the two media is the same, a wave moves from one medium to the other as if there is no … If the impedances of two media are very different, most of the wave energy is reflected back into the first medium and does not …
reflected; transmitted; ; change; travel into the second medium
When multiple waves pass through the same medium at the same time, the net displacement at a particular time and location in the medium is the …that would be caused by each wave if it were alone in the medium at that time. Mathematically, this statement can be written as …
sum of the displacements; ynet = y1 + y2 + …
the process of two or more waves of the same frequency overlapping is called
interference
constructive interference: places where the waves add to create a
larger disturbance
destructive interference: places where two waves add to produce a
smaller disturbance
the frequencies fn at which a string with fixed ends can vibrate are: fn =
nv/2L
antinodes reach the … on a standing wave
maximum displacement
nodes: points on a standing wave that do not … at all
vibrate
points on a standing wave vibrate
in phase
