Physics and Math Chapter 7: Waves and Sound

Question 1

Transverse waves

Answer 1

Have oscillations of wave particles perpendicular to the direction of wave propagation.

Question 2

Longitudinal waves

Answer 2

Have oscillations of wave particles parallel to the direction of wave propagations

Question 3

Displacement

Answer 3

Refers to how far a point is from the equilibrium position

Question 4

Amplitude

Answer 4

Magnitude of its maximal displacement

Question 5

Crest

Answer 5

the maximum point of a wave (point of most positive displacement)

Question 6

Trough

Answer 6

the minimum point of a wave (most negative displacement)

Question 7

Wavelength

Answer 7

the distance between two troughs or two crests

Question 8

Frequency

Answer 8

The number of cycles it makes per second. (Hz)

Question 9

Angular frequency

Answer 9

frequency in radians per second

Question 10

Period

Answer 10

number of seconds it takes to complete a cycle (inverse of frequency

Question 11

Interference

Answer 11

The ways in which waves interact in space to form a resultant wave.

Question 12

Constructive interference

Answer 12

when waves are exactly in phase with each other. The amplitude of the resultant wave is equal to the sum of the amplitudes of the two interfering waves

Question 13

Destructive interference

Answer 13

waves are exactly out of phase. resultant is equal to the difference in amplitude between the two interfering waves

Question 14

Partially constructive and partially destructive

Answer 14

occur when 2 waves are not quite perfectly in or out of phase. the displacement is equal to the sum of the displacements of the two interfering waves

Question 15

Traveling waves

Answer 15

have continually shifting points of maximum and minimum displacement

Question 16

Standing waves

Answer 16

produced by the constructive and destructive interference of two waves of the same frequency traveling in opposite directions in the same space.

Question 17

Antinodes

Answer 17

points of maximum oscillation

Question 18

Nodes

Answer 18

points where there is no oscillation

Question 19

Sound

Answer 19

produced by mechanical disturbance of a material that creates an oscillation of the molecules in the material.

Question 20

resonance

Answer 20

the increase in amplitude that occurs when a periodic force is applied at the natural resonant frequency of an object

Question 21

Damping

Answer 21

decrease in amplitude caused by an applied or nonconservative force

Question 22

What can sound not propagate through?

Answer 22

Vacuum

Question 23

What does sound propagate the fastest through?

Answer 23

Fastest - Solids
Liquids
Slowest - Gases

Question 24

As density increases, the speed of sound…

Answer 24

decreases

Question 25

pitch

Answer 25

related to frequency

Question 26

Doppler effect

Answer 26

a shift in the perceived frequency of a sound compared to the actual frequency of the emitted sound when the source of the sound and its detector are moving relative to one another.

Question 27

When source and the detector are moving towards each other…

Answer 27

Apparent > emitted

Question 28

When source and detector are moving away from each other…

Answer 28

Apparent

Question 29

When source and detector are moving in the same direction…

Answer 29

Apparent can be or =, depending on the relative speeds

Question 30

Shock waves

Answer 30

When the source is moving at or above the speed of sound — can form shock waves

Question 31

Intensity

Answer 31

Loudness or volume of sound related to a wave’s amplitude

Question 32

Intensity over distance

Answer 32

Intensity decreases over distance – some energy is lost to attenuation from frictional forces

Question 33

Strings and open pipes

Answer 33

support standing waves and the length of the string or pipe is equal to some multiple of half-wavelengths

Question 34

Closed pipes

Answer 34

also support standing waves and the length of the pipe is equal to some odd multiple of quarter-wavelengths

Question 35

How is sound used medically?

Answer 35

In ultrasounds