Placeholder Image

字幕列表 影片播放

  • An apple weighs about 1 newton, the world record for jet engine thrust is 570,000 newtons.

    一顆蘋果的重量大約是1牛頓 (譯注: 1牛頓約等於102公克重)

  • And the Saturn V rocket that launched people to the moon had a thrust of 33,360,000 newtons

    噴射引擎推力的世界紀錄則是57萬牛頓

  • But how can we measure forces this big accurately?

    載人登月計畫使用的土星五號火箭推力高達3千3百萬牛頓

  • Well, we need to ask this guy.

    話說回來,這麼大的力量我們是如何精確測量出來的呢?

  • Hi my name is Rick Seifarth I'm a physical scientist in the Mass and Force Group.

    這個問題讓我們找個專家來回答

  • Am I supposed to look at the camera?

    大家好,我叫Rick Seifarth,我是國家標準技術研究所(NIST)的物理學家

  • Sure.

    我應該要看著鏡頭講話吧?

  • Okay.

    不然呢?

  • You can look at anything you like.

    好吧!

  • Rick manages a dead weight machine that can apply 4,448,222 newtons.

    隨便你想看哪裡啦!(哈哈)

  • Why such a strange number? Because that's exactly equal to 1,000,000 pounds of force.

    Rick負責管理一台靜荷重設備,可提供高達4,448,222牛頓的力

  • There are twenty fifty thousand pound increments in this machine

    為什麼會是這個怪怪的數字?因為它剛好等於1百萬磅的力

  • 20 times 50 equals 1,000,000 pounds.

    這台機器裡面有20個50,000磅重的砝碼

  • Cumulatively that's 4.45 mega newton.

    20 x 5,0000磅 = 1,000,000磅

  • Elsewhere in the world, are there larger masses that people have calibrated?

    累計起來就是約445萬牛頓

  • I ask that question to every visitor we get and I've not gotten..

    這世界上有沒有其他人曾校準過比你們這裡更大重量的砝碼?

  • one response that says: yeah I know where bigger stuff is calibrated.

    這個問題我問過每一位參觀來賓,目前還沒有得到一個回答是:

  • So if I really want to go out on a limb and brag I'll say

    "有啊!真的有人校準過更大的東西!"

  • these are the largest mass objects ever calibrated.

    所以如果我真的想要出去大肆吹噓的話

  • Anywhere

    我敢說這些絕對是迄今被校準過的最大砝碼

  • The machine works like this, below ground are the 20 carefully calibrated masses.

    全世界最大的

  • Their weight is used to calibrate force sensors also called

    這機器的工作原理如下:在地面以下有20個經校準的砝碼

  • Force Transducers, in the lab upstairs.

    它們的重量被用來校準位於實驗室樓上的"力傳感器" (Force Transducer)

  • This is a one million pound capacity 4.45 mega newton,

    這個"力傳感器"可測到1百萬磅,相當於445萬牛頓

  • and this is 13.3 mega newtons, three million pounds force.

    這個則可以測到3百萬磅,相當於1,335萬牛頓的力

  • This is the biggest machine of it's type in the world, and obviously one of a kind.

    這台機器是這世界上同類型中最大的一台 ,所以顯然是獨一無二的

  • One of these,

    其中之一,

  • will be placed on the compression head right here.

    將被放置在這裡的重壓台上

  • Then, a hydraulic ram in the attic starts to raise the green lifting frame

    然後,在閣樓上的液壓油缸開始拉起 綠色升降架

  • And once the force transducer contacts the red loading frame,

    當"力傳感器"接觸到紅色負載架時

  • well then it starts lifting the weights downstairs.

    它就開始拉動樓下的砝碼

  • And as the lifting frame continues to rise, more and more of the

    隨著升降架繼續上升,越來越多的

  • 50,000 pound weights become suspended by the force sensor.

    50000磅砝碼被"力傳感器"懸吊起來

  • And since the weights create an accurately-known force,

    由於這些砝碼提供了精確的已知力

  • the readouts from the force transducer can be precisely calibrated.

    就可以用來精密地校準當下"力傳感器"的讀數

  • These devices are then sent out into the field.

    然後,這些已校準的"力傳感器"就可以送到現場使用。

  • Well literally, there's a test stand that's set up with one of these gizmos-

    舉例來說,有一種試驗台就有使用"力傳感器"這個元件

  • a force transducers - embedded in the test stand somewhere.

    它被嵌入在試驗台的某處

  • And so the rocket is fired up, perhaps ramped up, ramped down and those forces are monitored.

    當火箭被發動時,不論是逐步加速或減速,過程中的推力值都可以被監控

  • You know, in the old movies you'd hear: "go to 104% of power." Well, how do they know it's 104% of power?

    你在電影某幕中可能會聽到指令:“推力設定104%”,那麼他們是如何確定它真是104%?

  • Because somebody's measured it somewhere.

    那是因為某處有人正在測量它

  • When it comes to minimizing uncertainty, these guys aren't messing around.

    當談到盡量降低不確定性,這些傢伙可沒有掉以輕心

  • This piece right here is approximately 50,036.27 pounds of mass.

    這裡的一塊砝碼重量約為50,036.27磅

  • Approximately.

    只是大約?

  • Approximately, yes! [laughter]

    就是大約! [笑聲]

  • Think about that for a moment.

    讓我們停下來思考一下

  • Each of these pieces has a mass equivalent to ten minivans,

    這些砝碼中旳每一個重量都相當於10台休旅車

  • and their exact value is known to within several American nickels.

    而它們的重量誤差值卻只相當於幾枚五分錢硬幣

  • Just a few American nickels worth of difference?

    只有幾枚五分錢硬幣的差異??

  • Yeah.

    沒錯!

  • That tiny uncertainty is measured with respect to the very definition of the kilogram

    對於這樣微小不確定性的測定是基於千克的定義:"K20"原型

  • using K20 - that's the United States fundamental mass standard.

    這是美國的基本質量1千克標準品

  • This is done by comparing combinations of known weights, starting with K20, with larger unknown weights,

    這是通過從1千克(K20)開始的已知砝碼組合,和其他較大未知砝碼相比較來完成

  • gradually working up to larger and larger masses.

    逐步往上到越來越大重量的砝碼

  • For example, here a single 5-kilogram mass is compared to two 2s and a 1.

    例如,這裡有一個5千克的砝碼正在與一組由兩個2千克和一個1千克砝碼的組合來相比較

  • At some point in this process, they convert and start working in pounds, going from 50-pound masses to 500 pounds,

    在這過程中的某些階段,它們的單位將開始由千克轉換為磅,然後從50磅重的砝碼進行到500磅

  • and then 2500 pounds. And then, using a scale in the floor, to reach 10,000 pounds and then 20,000,

    再來到2,500磅。然後轉到落地型的大型磅秤,以達到10,000磅、20,000磅、

  • and finally 30,000 pounds.

    最終達到30,000磅

  • Combinations of these huge weights are then used to calibrate the 50,000-pound masses which form the weight stack.

    然後再用這些巨大的砝碼的組合來校準這些將用作於配重片的50,000磅砝碼

  • And we have to have that, because what we sell is the vertical force vector that's generated by these weights

    我們必須不厭其煩,因為這就是我們提供的服務:由這些配重片懸在重力場中所產生的精準垂直力矢量

  • hanging in a gravitational field. We sell that with an uncertainty attached to it of 0.0005%,

    我們服務的價值在於誤差只有0.0005%的精確度

  • five parts per million, so that means at full one million pounds of applied force, we guarantee that to be accurate - if you will -

    百萬分之五的誤差,意謂著在100萬磅的推力量測裡,如果你能接受5磅以內的不確定性,

  • within five pounds.

    我們可以保證數值的準確性

  • Not only does that mean the masses have to be accurately calibrated,

    然而,這不僅僅代表著這些配重片必需被精密地校準

  • it also means the gravitational acceleration at this location has to be taken into account.

    同時這也代表必須考慮到所在位置的重力加速度

  • It's actually slightly less than Earth's standard gravity, so an additional 600 pounds are required.

    因為所在地的地心引力實際上略小於地球的標準引力,因此需要補足額外的600磅重

  • Plus, the buoyant force must be counteracted,

    除此之外,還有空氣浮力必須被抵消

  • since these masses displace 125 pounds of air,

    因為這些配重片的體積所排除的空氣量為125磅 (產生125磅的浮力)

  • a further 125 pounds must be added to reach a million pounds of force.

    因此必須再加上125磅才能真正補足100萬磅的力

  • What strikes me as kind of amazing is that, like, this machine needs to exist, in a way.

    想到這台機器在某些方面上存在的必要性,讓我感到驚奇不已

  • When I would have thought about it, like how would Boeing measure its forces, I would have thought

    我曾好奇波音公司如何測量它的引擎推力量,我真有想過這事

  • OK, they just, you know, calibrate a device that works up to X but then they can, you know,

    他們也就只是依樣校準到若干個配重片

  • generalize. Well, generalize - you know what I mean, like - Yes!

    概括化。那麼,概括化 - 你知道我的意思,就像 - 是的!

  • There's an axiom that says "one physical test is worth a thousand expert opinions."

    有句至理名言:“一個物理測試抵得上一千名專家的意見”

  • And that has proven itself time and again, particularly in the world of physical testing.

    這句話經得起千錘百煉,尤其是在物理測試的領域

  • If you're getting on an airplane that somebody has built, are you willing to accept a 10% uncertainty on these numbers

    如果某人建造了一架飛機,它建造過程中的量測不確定性達到10%,你會敢坐嗎?

  • or do you want it to be - the uncertainty on these measurements to be down in the mud?

    或者你希望這些測量的不確定性能夠低到仆街?

An apple weighs about 1 newton, the world record for jet engine thrust is 570,000 newtons.

一顆蘋果的重量大約是1牛頓 (譯注: 1牛頓約等於102公克重)

字幕與單字

影片操作 你可以在這邊進行「影片」的調整,以及「字幕」的顯示

B2 中高級 中文 牛頓 傳感器 重量 推力 不確定性 機器

世界上最重的重量 (World's Heaviest Weight)

  • 8 0
    林宜悉 發佈於 2021 年 01 月 14 日
影片單字