# Physics – Chapter 19

Flashcard maker : Lily Taylor
What is a wiggle in time called?
a vibration
What do you call a wiggle in space and time?
a wave
What is the source of all waves?
something that is vibrating (or a medium)
What is meant by the period of a pendulum?
the time for one complete vibration
How is a sine related to a wave?
a sine curve is a pictorial representation of a wave produced by a simple harmonic motion
Peiod
the time of a to-and-fro swing
Amplitude
the distance from the midpoint to the crest (or trough) of the wave
Wavelength
-the distance from the top of one crest to the top of the next crest
-the distance from the bottom of one trough to the bottom of the next trough
-the distance between any successive identical parts of the wave
Frequency
the number of to-and-fro vibrations it makes in a given time (usually 1 second)
Frequency=1/period
How many vibrations per second are represented in a radio wave of 101.7 MHz?
101.1 * 1,000,000 (MHz) = 101,700,000
How do frequency and period relate to each other?
-the frequency and period are the inverse of each other
Frequency = 1/Period
Period = 1/Frequency
In one work, what is it that moves from source to receiver in wave motion?
energy
Does the medium in which a wave travels move with the wave? Give examples to support your answer.
No. If the salt water in an ocean waved moved with the wave, the land would become flooded as the salt water would not stop moving forward. You can also visualize this with a cork floating in the ocean. As the waves move by, the cork seems to stand still in the same position.
What is the relationship among frequency, wavelength, and wave speed?
In what direction are the vibrations relative to direction of wave travel in a transverse wave?
the motion of the medium is transverse (or perpendicular) to the direction the wave travels
In what direction are the vibrations relative to the direction of wave travel in a longitudinal wave?
motion is along (or parallel) the direction of the wave
The wavelength of a transverse wave is the distance between successive crests (or troughs). What is the wavelength of a longitudinal wave?
the distance between successive compressions or, equivalently, the distance between successive rarefactions
What is meant by the superposition principle?
when more than one wave occupies the same space at the same time, the displacements add at every point
Distinguish between constructive interference and destructive interference.
constructive-when the crests of one wave overlaps the crest of another, their individual effects add together to produce a wave of increased amplitude

destructive-when the crest of one wave overlaps the trough of another, their individual effects are reduced

What kinds of waves can show interference?
all waves
What is a node?
parts of the wave that appear to standing still
What is an antinode?
regions of maximum displacement and maximum energy
Are standing waves a property of transverse waves, of longitudinal waves, or of both?
Both
In Doppler effect does frequency? Does wavelength change? Does wave speed change?
frequency – yes
wavelength – yes
wave speed – yes
Can the Doppler effect be observed with longitudinal waves, with transverse waves, or with both?
Both
What is meant by a blue shift and a red shift for light?
Blue shift = increased frequency of light. Red shift = decreased frequency of light.
How fast must a bug swim to keep up with the waves it produces? How fast must it move to produce a low wave?
right along with the leading edge of the waves; faster than wave speed
How fast does a supersonic aircraft fly compared with the speed of sound?
the aircraft surpasses the speed of sound
How does the V shape of a bow wave depend on the speed of the source?
after the speed of the source exceeds wave speed, increased speed of the source produces a narrower V shape
A bow wave on the surface of water is two dimensional. how about a shock wave in air?
3 dimensional
True or false. A sonic boom occurs only when an aircraft is breaking through the sound barrier. Defend your answer.
Fasle. A sonic boom occurs when any object breaks the sound barrier
True or false. In order for an object to produce a sonic boom, it must be “noisy”. Give 2 examples to support your answer.
False. Bullet and lion whip.