unit 4 test

Question 1

what are the two types of waves?

Answer 1

a transverse wave, and a longitudinal one.

Question 2

what is a transverse wave?

Answer 2

a wave where particles are displaced perpendicular to the direction of the wave. we use this one the most.

Question 3

what is a longitudinal wave?

Answer 3

a wave where particles move in the same direction of the wave motion. like a spring.

Question 4

what is a crest?

Answer 4

the top of a wave

Question 5

what is a trough?

Answer 5

the bottom of a wave

Question 6

what is amplitude?

Answer 6

the distance from the middle of a wave to the crest or trough.

Question 7

what is a compression?

Answer 7

a spot on a longitudinal wave where the coils are compressed. this is the maximum density.

Question 8

what is a rarefaction?

Answer 8

the part of a wave where coils are spread apart. this is the point of minimum density.

Question 9

what is frequency?

Answer 9

the amount of cycles that happen in a unit of time. measured in hertz.

Question 10

what is period?

Answer 10

the time to complete a wave

Question 11

how to measure the speed of waves?

Answer 11

v=f λ. measured in hertz i think. length is 1/2 λ. λ is v/f

Question 12

what does loudness effect?

Answer 12

the amplitude. loud= large

quiet= small

Question 13

what does pitch effect?

Answer 13

the frequency. high pitch= high frequency

low pitch = low frequency

Question 14

what does quality affect?

Answer 14

the wave form. pure is simple, rich is complex (includes harmonies and cool waves), and noise is irregular and doesnt have a real wave look.

Question 15

what is the principle of superposition?

Answer 15

the amplitude of two interfering waves is the sum of both waves combined

Question 16

what is beat frequency?

Answer 16

two vibrations with similar frequencies. sound signals interfere and its heard as a separate note.

Question 17

what is resonance?

Answer 17

two things vibrating in harmony resonate. this is like the phet simulation where that wave got really really big. like pushing a swing

Question 18

what is the doppler effect?

Answer 18

things push their wave lengths, wavelengths in front are shorter and behind they’re longer. its used by police,weather people.

Question 19

when something is coming at you what does it sound like?

Answer 19

the pitch is higher bc wavelengths are shorter

Question 20

what is a shockwave?

Answer 20

happens when something moves at speed of sound. waves superimpose eachother, when you break this barrier, you get a sonic boom. this is what happens with thunder.

Question 21

what is a node?

Answer 21

when the lines all intercept on the axis. fixed ends have nodes

Question 22

what is an antinode?

Answer 22

when the lines are not on the axis. they are in a crest or a trough. open ends have antinodes

Question 23

what happens when a wave undergoes a fixed end?

Answer 23

the wave is reflected and inverted along the axis.

Question 24

what happens when a wave undergoes an open end>

Answer 24

its reflected with the same orientation as the incoming wave.

Question 25

how do harmonics work.

Answer 25

each harmonic goes up by half a wavelength. 1st harmonic:
fixed on both ends = 1/2 λ
fixed on one end= 1/4 λ
open both ends = 1/2 λ

Question 26

how does hearing go in the outer ear?

Answer 26

the ear collects the soundwaves and directs them into the middle ear, vibrates eardrum, a part of the middle ear.

Question 27

how does hearing go in the middle ear?

Answer 27

the vibrartions get magnified on the eardrum, that is very much like a regular drum. bones in the middle ear magnify the vibrations as well. they are the stirrup, hammer, and anvil.

Question 28

how does hearing go in the inner ear?

Answer 28

it goes into the cochlea, causes pressure waves that pass over tiny hairs, which converts it to little chemical signals of sounds that go from the auditory nerve into the brain.

Question 29

how does echolocation work in bats, and dolphins/

Answer 29

they send out high frequencies that hit nearby objects and reflect back off towards the animal. sound comes from sacks by the blowhole, and gets back to the fat filled cavity in their lower jaw.

Question 30

how do elephants do echolcation?

Answer 30

they deliver long, low frequency sounds that travel through the earth and they can feel them in their feet.