Question

Which equation can be used to model simple harmonic motion?

A. d=acos(wt)

B. d=asin(wt)+k

C. d=cos(awt)

D. d=acos[w(t+k)]

****My answer: A

is that right?? :)

Answer 1

sorry... here are the answer choices... :)

answer choices A,B,C,D from top to bottom :)

Answer 2

what do y'all think? is A right? :)

Answer 3

no i don't mean you, i mean the person that made the question is making me sad

Answer 4

hahaha ohhh i see.. lol idk... :/

do u get it? does it look like i got it right?? i'm not 100% sure :/

Answer 5

i debate the wording of this question, but either way http://en.wikipedia.org/wiki/Harmonic_oscillator#Damped_harmonic_oscillator

Answer 6

Simple harmonic motion is Asin(omega t)

Answer 7

i would say d

Answer 8

how come? :/

Answer 9

oh we have a conflict.

Answer 10

hmm? ;/

Answer 11

@eSpeX you need a phase shift somewhere in there ... .

Answer 12

@jim_thompson5910

Answer 13

Well for the available answers, 'b' takes the shift into account.

Answer 14

that's a vertical shift ...

Answer 15

not a horizontal shift

Answer 16

if k in d is φ then its right

Answer 17

Then it has to be 'A' since the cos of theta is a shift of 90 from sin.

Answer 18

sorry without the parenthese

Answer 19

i'm confused lol :/

Answer 20

examploes of different shifts http://i.imgur.com/OWWlTo0.png

Answer 21

d is right if it is d=acos(wt + k) if k is φ

Answer 22

@eSpeX no wt cannot have a shift in it. w and t are expressions of a variable. variables cannot have operators inside in this

Answer 23

thats like saying x=y+2 in a taylor series expansion

Answer 24

Simple Harmonic Motion is A i believe

Answer 25

@doppler, but 'd' isn't wt+k, it is w(d+k)

Answer 26

@AnElephant you're not including a shift

Answer 27

@RONNCC A is cos(wt) which is sin(wt + 90)

Answer 28

yeah only a can be right

Answer 29

ueh i give up just put A. it depends on the kind of harmonic motion. the simplest simplest case would have the shift as 0 as you're taking it from where you want. thats why this question is bad

Answer 30

A is the basic form of a harmonic motion curve...

Answer 31

ooohhh okay.. so the answer is A? :/

and this question is officially and poorly made question? LOL

Answer 32

*Simple harmonic motion curve

Answer 33

just say A

Answer 34

oh okay hahaha thanks for all the help!!! i really appreciate it :)

Answer 35

technically A and D are the same thing

Answer 36

but D simplifies to A

Answer 37

assuming no shift

Answer 38

quoting textbook ''the complete general solution is x=A1cosωt + A2sinωt''

Answer 39

ohh they are? weird!!!

Answer 40

''if you have A1=Acosφ and Α2=-Αsinφ then substitution gives x=Acos(ωt + φ)''

Answer 41

so it is A with φ=0 but still a little vague as ron said

Answer 42

@iheartfood cos(x) = sin(x + Pi/2)

Answer 43

Yeah, my old textbook does not account for phase shifts in the simple harmonic motion chapter

Answer 44

oh okay.... thanks a bunch y'all :)


yup i agree... this is vague :(

Answer 45

correct mathematically wrong physically