Unit 7

Question 1

Doppler Effect

Answer 1

the change in the observed frequency of a wave because of the motion of the source or the observer toward or away from the other; the frequency increases when the source and observer approach each other and decreases when they move apart

Question 2

Acoustics

Answer 2

the science and study of sound, including its production, propagation, and effects; also, qualities determining the ability of an enclosure

Question 3

Amplitude

Answer 3

\AM-pluh-tood\
in a wave, the maximum displacement of a wave from its rest position—that is, distance from rest to crest or rest to trough

Question 4

Compression

Answer 4

in a medium through which sound is passing, a high-pressure region of a sound wave

Question 5

Constructive Interference

Answer 5

effect that occurs when two waves with synchronized crests and troughs meet

Question 6

Destructive Interference

Answer 6

effect that occurs when two waves with crests and troughs that are out of phase meet, effectively canceling each other out to zero amplitude at a point

Question 7

Frequency

Answer 7

the number of waves that pass through a point during a specific amount of time

Question 8

Hertz

Answer 8

the SI-derived unit of frequency in the metric system; it is a unit equal to one cycle per second

Question 9

Longitudinal Waves

Answer 9

for mechanical waves, waves in which the movement in the medium is parallel to the direction the wave is traveling

Question 10

Medium

Answer 10

\MEE-dee-uhm\
substance that is the means of transmission of a force or effect; in the case of waves, air, water, other gases, and solid earth are all mediums through which different types of waves can travel

Question 11

Period

Answer 11

the time for a wave, or one cycle of a repeating wave, to pass a location

Question 12

Pitch

Answer 12

in music and acoustics, refers to the frequency of a given tone in that pitch is the perceived highness or lowness of a sound—high frequency sound waves are associated with high pitch, and low frequency sound waves are associated with low pitch; frequency can be physically measured, whereas pitch is perceived, therefore pitch is not synonymous with frequency

Question 13

Rarefaction

Answer 13

in a medium through which sound is passing, a low-pressure region of a sound wave

Question 14

Sonic Boom

Answer 14

\SAH-nik\
piled-up sound waves manifested as a violent shock wave propagating behind an object that is traveling at supersonic speed (faster than the speed of sound); the object catches up with its own noise and at higher speeds forces the sound ahead of itself faster than the noise would normally go, creating the piled-up and booming sound effect

Question 15

Speed

Answer 15

the rate at which an object changes position

Question 16

Standing Wave

Answer 16

a pattern formed when two waves of the same amplitude and frequency move simultaneously through a medium in opposite directions (the wave appears to oscillate but not propagate); also stationary wave

Question 17

Transverse Waves

Answer 17

for mechanical waves, waves in which the movement in the medium is perpendicular to the direction the wave is traveling

Question 18

Traveling Wave

Answer 18

a wave that continuously carries energy away from its source

Question 19

Velocity

Answer 19

\veh-LAH-suh-tee\
the rate at which an object changes position when traveling in a certain direction, expressed as a rate: the distance an object traveled from one position to the next divided by the time it took to travel the distance

Question 20

Wavelength

Answer 20

distance from one point on a wave to the next same point on a wave (for example, distance from crest to crest or trough to trough); distance of one wave cycle