Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT > Periodic motion, waves and sound > Flashcards

Periodic motion, waves and sound Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards
1
Q

angular freq, w =

A

w = √(k/m)

k = stiffness in spring
m = mass
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

simple harmonic motion, F =

Why is it neg?

A

F = -kx

Neg to show that restoring force is in opposite direction of the displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

simple harmonic motion, a =

A

a = w^2x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the eq point

A

point where F = 0.

the point about which the particle or mass oscillates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the linear restoring force?

A

always directed back to eq pt

mag is directly proportional to displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the 2 types of simple harmonic motion?

A

Mass-spring

simple pendulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the equation for displacement of a particle from eq pt?

A

x = Xcos(wt)

X = particle amplitude (largest distance from eq pt)
t = time
w = 2pif = 2pi/T
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Equation for angular freq, w =

A

w = 2pif

w= 2pi/T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

potential E of spring at rest, U =

A

U = 1/2kx^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the U for a pendulum?

A

U = mgh where h is height above lowest point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the U and K at eq pt?

A

U = 0

K is max (kinetic E)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

in SHM (simple harmonic motion), do f and T depend on amplitude?

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

k = ?

For mass=spring

for simple pendulum

A

k = spring const

k = mg/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

w =

mass-spring
pendulum

A

w = √ (k/m)

w = √(g/L)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

T =

mass-spring
pendulum

A

T = 2pi√(m/k)

T = 2pi√(L/g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

f =

mass-spring
pendulum

A

f = 1/T = w/2pi

f = 1/T = w/2pi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

K

mass-spring
pendulum

where is Kmax?

A

K = 1/2mv^2 Max at x=0

K = 1/2mv^2 Max at a=0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

U =

mass-spring
pendulum

Umax?

A

U = 1/2kx^2 Mat at +/-x

U = mgh Max at a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

For SHM where does max acc happen?

A

always at Fmax. which occurs at max displacement, x

20
Q

what is a transverse wave?

A

particles oscillate perpendicular to direction of wave motion.

Think waving a slinky back and forth on the ground

21
Q

longitudinal waves

A

oscillate along direction of wave motion

think pushing slinky

22
Q

wave equation y =

(where y is the displacement of a particle

A

y = Ysin(kx-wt)

where Y = amplitude
k = wave number

23
Q

what is wavelength, h

A

the distance from one max crest to the next

24
Q

what is f and what are the units

A

freq is the # of waves passing a pt per second.

Hz

25
Q

velocity of wave, v =

A

v = hf

26
Q

wave number k =

A

k = 2pi/h

27
Q

what is phase difference?

what if it is 0?

A

phase diff is how in step 2 waves are

at 0, they are identical

28
Q

what is the principle of superposition?

constructive vs. destructive

A

when waves interact, the result is the sum of the waves

constructive, waves are in phase and amplitudes add

destructive - out of phase, amp is difference

29
Q

what is a traveling wave?

A

one side is fixed, the other end is moved from side to side. Think of moving a string side to side, the other part is attached to the wall.

Results in an incident wave, which travels from the open end (your hand), to the wall
Also in a reflected wave, the wave that travels back after hitting the wall.

If you keep moving your hand, there are 2 waves moving at once then.

30
Q

what is a standing wave?

what are the parts?

Besides strings, where can standing waves occur?

A

wave form that has 2 fixed ends. So it remains stationary, but the amplitude fluctuates.

Like a jump rope, only imagine you’re not moving your arms.
node - pt that remain at rest
antinode - halfway between nodes, amplitude changes. (max, min, max, min)

standing waves occur in strings, also in pipes, closed

31
Q

resonance:
natural freq
mass-spring?
pendulum?

A

the natural freq is the normal mode of vibration, no external forces.
mass spring will have infinite natural:
f = 1/2pi[√k/m

pendulum as 1 natural freq:
f = 1/2pi√g/L

32
Q

what is forced oscillation?

is the amp usually large or small?

A

forced oscillation is when a periodically varying force is applied to a systme.
amp usually small
larger is F is close to natural freq

33
Q

what does it mean if the system is resonating?

A

forced oscillation F = nat freq.
amp is at max, if system was frictionless, forced oscillation would continuously add to system and amp would get infinitely large

34
Q

sound waves are what kind of waves?

A

longitudinal

35
Q

What are the 3 classifications of sound waves?

A

infrasonic = 20,000 Hz

36
Q

what is intensity of sound?

P =

A

rate at which E is transported across perp surface by wave

P = IA
where P is power
I = intensity
A is area

37
Q

how is sound level measured

A

B = 10logI/Io

where Io = reference intensity

38
Q

can pitch be measured?

A

no

39
Q

How can sound be produced?
solid?
vibration?

A

vibration of solids, air mcules put in motion, eg string instrument, piano (moving parts)

acoustic viibration - organ pipes, flute, no moving parts just air vibrating

40
Q

what are beats?

A

beats are heard when 2 waves of nearly the same freq are superimposed. The waves are added together, leading to a periodic variation of loudness. = beats!

freq of beats = |diff in indiv freq|

41
Q

Doppler effect

A

perceived f is different than real:

f’ = f [(v+/-vD)/(v+/-vS)]

42
Q

doppler effect, eq when detector is moving toward source of source moves toward detector

A

vD is + Think the source and detector are moving closer to each other, so the detector is getting close to detection

43
Q

when detector moves away or source moves away

A

vD is - Think the detector is getting further away from detection

44
Q

Standing waves: wavelength, “h” and f

strings

A

string:
h = 2L/n where n is harmonic
f = nv/2L where v = wave speed

45
Q

standing waves, h and f for

open pipes

closed pipes

A

open:
h=2L/n
f = nv/2L

closed:
h = 4L/n
f = nv/4L

46
Q

higher harmonics have longer or short h?

A

they have shorter.

Think how many “waves” can you get in fixed position? higher harmonics mean you can get more, 3rd harmonic, you can fit 3 full waves in the fixed space, so lengths are shorter

MCAT (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions