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 propagation

Question 3

Crest

Answer 3

point of most positive displacement

Question 4

Trough

Answer 4

point of most negative displacement

Question 5

Wavelength

Answer 5

the distance between two crests or two troughs

Question 6

Frequency

Answer 6

• the number of cycles a wave makes per second
• expressed in hertz (Hz)
• angular frequency the same thing but measured in radians per sec

Question 7

Wave speed

Answer 7

v= F (lamda)

Rate at which a wave transmits the energy or matter it is carrying

Question 8

Wave period

Answer 8

T= 1/f
Time needed to complete a wave cycle
-the inverse of frequency

Question 9

Constructive interference

Answer 9

• occurs when waves are exactly in phase with each other

- amplitude of the resultant wave is equal to the sum of the amplitudes of the two interfering waves

Question 10

Destructive interference

Answer 10

• occurs when waves are exactly out of phase with each other

- amplitude of resultant wave is equal to the difference in amplitude between the two interfering waves

Question 11

Traveling waves

Answer 11

have continuously shifting points of maximum and minimum displacement
- nodes and antinodes move with wave propagation

Question 12

Standing waves

Answer 12

produced by the constructive and destructive interference of two waves of the same frequency traveling in opposite directions in the same space
- nodes and antinodes do not move with wave propagation

Question 13

Antinodes

Answer 13

points of maximum oscillations

Question 14

Nodes

Answer 14

points where there is no oscillation

Question 15

Resonance

Answer 15

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

Question 16

Damping

Answer 16

decrease in amplitude caused by an applied or nonconservative force

Question 17

Properties of sound

Answer 17

• propagates through all forms of matter (but not a vacuum)
• propagates fastest through solids, followed by liquids, and is slowest through gases
• within a medium, as density increases, the speed of sound decreases

Question 18

Shock waves

Answer 18

• highly condensed wave

- occurs when the source is moving at or above the speed of sound

Question 19

Intensity is related to a wave’s

Answer 19

amplitude

Question 20

Intensity … over distance by a factor of …

Answer 20

decreases, distance squared

Question 21

Attenuation

Answer 21

energy lost from a sound wave due to frictional forces

Question 22

Intensity equation

Answer 22

I=P/A
P=power
A=area

Question 23

Open pipes and strings

Answer 23

• support standing waves

- length of the string or pipe is equal to some multiple of half-wavelengths

Question 24

Closed pipes

Answer 24

• support standing waves

- length of the pipe is equal to some odd multiple of quarter-wavelengths

Question 25

Ultrasound

Answer 25

- uses high frequency sound waves outside the range of human hearing to compare the relative densities of tissues in the body - uses travel time of the reflected sound to calculate distance