- #1

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why we use cosine and sine in simple harmonic motion?

why we use particularly cosine with potential energy and sine with kinetic energy of simple harmonic oscillator?

regards

- Thread starter saba sha
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- #1

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why we use cosine and sine in simple harmonic motion?

why we use particularly cosine with potential energy and sine with kinetic energy of simple harmonic oscillator?

regards

- #2

mfb

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- #3

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thanks sir

but why we use these sine and cosine?

what these sine and cosine represent?

but why we use these sine and cosine?

what these sine and cosine represent?

- #4

mfb

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- #5

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Unless you specifically know the gender of the person you are responding, please do not assume that all of us here are males. You are insulting the many female physicists, physics students, and participants in this forum.thanks sir

but why we use these sine and cosine?

what these sine and cosine represent?

Zz.

- #6

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Mathematically, as mfb said, the summation of a sine and cosine is the solution to the differential equation that governs simple harmonic motion. For a mechanical oscillator, this equation is mx''+kx = 0, and the general solution is x(t) = c1*cos(wt+p)+c2*sin(wt+p). If you want a more intuitive understanding, you must realize that sine and cosine provide us a way to quantify circular motion. Conveniently, we can express the movement of an oscillator as a function of cosines and sines that have a constant angular frequency.

Here is a good animation that will hopefully make things more clear: In that animation, picture the oscillator as being the up and down movement of that rod as it goes around the circle, which is simply the sine wave.

Here is a good animation that will hopefully make things more clear: In that animation, picture the oscillator as being the up and down movement of that rod as it goes around the circle, which is simply the sine wave.

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- #7

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- #8

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Yes ma'am.Unless you specifically know the gender of the person you are responding, please do not assume that all of us here are males. You are insulting the many female physicists, physics students, and participants in this forum.

Zz.

- #9

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!!!!!! are you going to check every post for such 'serious' infringments ??Unless you specifically know the gender of the person you are responding, please do not assume that all of us here are males. You are insulting the many female physicists, physics students, and participants in this forum.

Zz.

What about dorks ????

Assuming someone is male is not an insult to anyone unless someone wants to take it as an insult.

Have there been many complaints about this?

Come on look at the questions!!!!

- #10

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Kinetic energy is to do with velocity and v = dx/dt so if x is a Cos function then v is a Sin function v = ωASin(ωt).

Hope this helps sir/madam

- #11

sophiecentaur

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Would "Oh wise one" be appropriate?Unless you specifically know the gender of the person you are responding, please do not assume that all of us here are males. You are insulting the many female physicists, physics students, and participants in this forum.

Zz.

This gender thing is, indeed, a general problem. The word "they" tends do be used for "he or she" and it is a bit gramatically unsatisfactory. I wonder whether we could have a ruling on this from the boffins in PF Towers?

- #12

sophiecentaur

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Sine and Cosine are Mathematical Functions. They do not actually represent anything but 'describe' how variables are related to each other. In this case it's how one variable (a general displacement) varies with another variable (time).thanks sir

but why we use these sine and cosine?

what these sine and cosine represent?

I could give an alternative verbal description of a harmonic oscillation: the displacement varies regularly on either side of a mean position, as time progresses, and this variation is smooth, is faster whilst the displacement is at the mean position and blah blah, etc. etc. . . . . . but the mathematical description is more accurate and allows you to calculate and predict in detail.

I know Maths can often annoy people because it is difficult to grasp but without it, Science is very limited. You need to 'join the Maths club' at some level, at least, of you want to advance knowledge to any useful level.

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