Waves and Periodic Motion, Sound and Solids

Question 1

Formula for simple harmonic motion

Answer 1

X= Acosωt or X=Asinωt

Question 2

Frequency Factor

Answer 2

ω; related to frequency but is no the frequency. Their relationship is proportional

Question 3

Phase shift of a wave to the right

Answer 3

x= Acos(ωt-Ф); over all subtracting

Question 4

Phase shift of a wave to the left

Answer 4

X=Acos(ωt+Ф); over all adding

Question 5

The period (T) is

Answer 5

The duration of time for one given event in a group. T = 1/ƒ

Question 6

The frequency (ƒ) is

Answer 6

The amount an event occurs in a given time ƒ = 1/T; measured in Hz

Question 7

Formula for a spring

Answer 7

ω = √k/m “Whack em”

Question 8

Formula for a pendullum

Answer 8

ω = √g/L “Wiggle”

Question 9

Formula for Vmax in simple harmonic motion

Answer 9

Vmax = Aω

Question 10

Formila for amax in simple harmonic motion

Answer 10

amax = Aω^2

Question 11

When dealing with pendullum how does the mass of the object affect its period/frequency?

Answer 11

The mass is irrelevant

Question 12

Hook’s Law

Answer 12

F = -kx

Question 13

Formula for elastic potential energy

Answer 13

P.E. = (1/2)(kx^2)

Question 14

How are the “pulling force” and the displacement in a spring related

Answer 14

They will point in the same direction

Question 15

How are the “force of the spring” and the displacement of a spring related

Answer 15

They will point in opposite directions

Question 16

At equilibrium a spring experiences

Answer 16

Only K.E. Vmax F = 0 a = 0

Question 17

At the extremes a spring experinces

Answer 17

V = 0 a max K.E. = 0 X = A (max amplitude) Only P.E.

Question 18

How are K.E. + P.E. Related to each other at the equilibrium position

Answer 18

They are equal to each other K.E. = P.E. (Elastic)

Question 19

Longitudinal Waves

Answer 19

Medium moves in direction of the wave

Question 20

Transverse waves

Answer 20

Medium moves perpendicular to the wave

Question 21

Formula for velocity in relation to sound

Answer 21

λƒ = v Vsound = ~343 m/s

Question 22

What is the order of medium (fastes -> slowest) in which sound travels

Answer 22

S > l > g Sound generally travels faster in solids than in liquids and gases

Question 23

Formula for speed in sound in solids/liquids

Answer 23

V ∝ √1/ρ **Only use this to compare solids to solids or liquids to liquids**

Question 24

Formula for speed in gases

Answer 24

V ∝ √P/ρ

Question 25

Formula for standing waves in a pipe open at both ends or a rope with both ends fixed

Answer 25

λn = 2L/n n = 1,2,3..etc

Question 26

Formula for standing waves in a pipe open at one end

Answer 26

λn = 4L/n n = odd #’s

Question 27

n=1 is

Answer 27

The first harmonic or the fundamental frequency

Question 28

Beat frequency

Answer 28

Difference between two frequencies of two different sound waves i.e. 190Hz - 180Hz = 10Hz is the Beat Frequency

Question 29

Formula for Intensity

Answer 29

I = P/A = P/4πr^2

Question 30

Every factor of 10x equals 10dB of intensity

Answer 30

10x loud = 10dB 100x = 20dB 1000x = 30 dB

Question 31

Formula for intensity level (not intensity)

Answer 31

β = 10log(I/Io)

Question 32

Lowest intensity humans can hear

Answer 32

Io = 10^-12 (W/m^2)

Question 33

Doppler Effect formula

Answer 33

ƒo = ƒs (V ± Vo/ V ± Vs)

Question 34

ƒo \> ƒs

Answer 34

Object and source are moving towards each other

Question 35

ƒo \< ƒs

Answer 35

Object and source are moving away from each other

Question 36

If possible calculate the percentage of wavelengths in respect to the speed of sound

Answer 36

i.e. (343 m/s)/(15 m/s) ~ 22% change

Question 37

Young’s Modulus for stretching and compressing

Answer 37

F/A = Y (ΔL/Lo)

Question 38

Shear Modulus for Shear Defromation (tilting of a large book)

Answer 38

F/A = S (ΔX/Lo)

Question 39

Bulk Modulus for Volume Deformation

Answer 39

ΔP = -B (ΔV/Vo)

Question 40

Overtones

Answer 40

Question 41

efficiency of heat formula

Answer 41

e = 1 - (Tc/Th)

Question 42

First harmonic formula

Answer 42

f1 = nv/4L (pipe open at one end) f1 = nv/2L (pipe open at both ends)

Question 43

Frequency of a wave when you aren't given the speed

Answer 43

f = # cycles/time

Question 44

Formula for period of a pendullum

Answer 44

T= 2π√1/g