Name: 奇特的旋轉管 - Numberphile (Strange Spinning Tubes - Numberphile)
Uploaded: 2021-01-14T10:41:52.000Z
Duration: 12 min 53 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

whose ends have been colored black and orange

and because it is spinning around the middle

a priori, there is no reason why you would see black better than orange

And every time we seem to be seeing black.

but you don't like black, I'm going to shake it

It's not a matter of launching from right to left

because I can launch it with my left hand and it's still orange.

so I'm going to rub it against my black hair

and that changes the color again, and it's black.

So the first mystery is why sometimes do we see black and sometimes orange?

Why four? It's not as if I'm launching it with very much care.

Its initial conditions seem to be random.

Now, this time I'm going to show you black.

And when I press down the orange end and launch

I'd like to begin by giving you a zeroth order theory,

and then we'll do the full theory later on.

So the zeroth order theory goes as follows...

can be thought of as a combination or superposition of two motions.

the whole thing is spinning like this around the vertical axis.

At same time, this thing spins around it's own axle.

Let's say for the time being that we launch it by pressing down the black end, okay.

the... rotation that I gave the black end is a back spin like this,

which means the orange end is going in top spin.

So that's a rotation which is also going forward.

So the revolution makes it advance like this

but the rotation which is like... like this

So, the rotation and revolution ADD to each other,

let's look at the black end that I pinch down.

Well again, the revolution... the revolution will make it advance like this.

But at this end, the rotation is back spin

so the rotational speed is actually pointing backward.

So those two speeds subtract from each other

And the fact of the matter is that the end that we see better is the end that is moving slower

and the end that's moving faster we don't see so well.

and the zeroth order theory is that black end is...

and the orange end, the fast end, we don't see.

but you see, this explanation, zeroth order as I called it

first of all, why is it that we see the slow end rather than the fast end?

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奇特的旋轉管 - Numberphile (Strange Spinning Tubes - Numberphile)

aspect

exaggerate

advantage

combination