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世界上最重的重量有多重?

World's Heaviest Weight

一个苹果重约1牛顿
An apple weighs about 1 newton,
喷气式发动机推力的世界纪录是570,000牛顿
the world record for jet engine thrust is 570,000 newtons.
将人类带上月球的土星5号运载火箭的推力是33,360,000牛顿
And the Saturn V rocket that launched people to the moon had a thrust of 33,360,000 newtons.
那么我们是如何精确的测量出这些数据呢?
But how can we measure forces this big accurately?
好 我们来问问这个人
Well, we need to ask this guy.
你好 我叫瑞克·赛法特 是Mass and Force集团的物理学家
Hi,my name is Rick Seifarth. I’m a physical scientist in the Mass and Force Group.
我是不是应该看着摄像头?
Am I supposed to look at the camera?
是的
Sure.
好吧
Okay.
你想看哪里就看哪里
You can look at anything you like.
瑞克管理着一个能提供4,448,222牛顿的极限重力工具
Rick manages a dead weight machine that can apply 4,448,222 newtons.
为什么是这么奇特的数字?因为这完全相当于1,000,000磅的重量
Why such a strange number? Because that’s exactly equal to 1,000,000 pounds of force.
这个机器每一节是五万磅
There are twenty fifty thousand pound increments in this machine,
20乘以50就是1,000,000磅
20 times 50 equals 1,000,000 pounds.
总共相当于4,450,000牛顿
Cumulatively that’s 4.45 mega newton.
世界的其他地方还有像这样精准的大型物质吗?
Elsewhere in the world, are there larger masses that people have calibrated?
我向每一位访客问了同样的问题 但还没有
I ask that question to every visitor we get and I’ve not gotten..
一个人回应说:嗯我知道在哪
one response that says: yeah I know where bigger stuff is calibrated.
所以如果我真的想自吹自擂 我会说
So if I really want to go out on a limb and brag I’ll say
这是有史以来最大的精准测量物体
these are the largest mass objects ever calibrated, anywhere
机器的工作原理是这样的 地下有20块精心校准的物体
The machine works like this, below ground are the 20 carefully calibrated masses.
通过它们的重量来校准力传感器 这个部分也叫做重力传感器 在实验室楼上
Their weight is used to calibrate force sensors also called Force Transducers, in the lab upstairs.
这是一百万磅约4,450,000牛顿
This is a one million pound capacity 4.45 mega newton,
这是13,300,000牛顿,三百万磅的力
and this is 13.3 mega newtons, three million pounds force.
在同类机器中 这是世界上最大的 而且很显然是独一无二的那种
This is the biggest machine of it’s type in the world, and obviously one of a kind.
其中一个会被放在那边的压缩端上
One of these, will be placed on the compression head right here.
然后在顶端的液压油缸开始提起绿色的提升框架
Then, a hydraulic ram in the attic starts to raise the green lifting frame
当测力传感器接触到红色的装载架
And once the force transducer contacts the red loading frame,
机器就开始吊起下端的砝码
well then it starts lifting the weights downstairs.
随着吊架持续上升 50,000磅重的砝码被力传感器一个又一个的吊起
And as the lifting frame continues to rise, more and more of the 50,000 pound weights become suspended by the force sensor.
一旦砝码形成准确的力
And since the weights create an accurately-known force,
测力传感器的资料解析装置能得出精确的数据
the readouts from the force transducer can be precisely calibrated.
这些数据随后会输出到扫描场
These devices are then sent out into the field.
这个测试标准被准确的设置在其中的一个装置
Well literally, there’s a test stand that’s set up with one of these gizmos-
即测力传感器里的某个部分
a force transducers – embedded in the test stand somewhere.
所以火箭点火 斜升 斜降的力都是被监控的
And so the rocket is fired up, perhaps ramped up, ramped down and those forces are monitored.
在老电影里你常常能听到:“力量推进到104%”那他们是怎么知道哪里是104%的力呢?
You know, in the old movies you’d hear: “go to 104% of power.” Well, how do they know it’s 104% of power?
那是因为有人在别处测量它
Because somebody’s measured it somewhere.
当它的不确定性降低 这些东西就不会无法控制
When it comes to minimizing uncertainty, these guys aren’t messing around.
这个机器每一片差不多50,036.27磅重
This piece right here is approximately 50,036.27 pounds of mass.
差不多
Approximately.
对的 差不多[笑声]
Approximately, yes! [laughter]
可以想象一下
Think about that for a moment.
每一片的重量相当于十辆小型货车
Each of these pieces has a mass equivalent to ten minivans,
它们和几片美国镍片的意义是一样
and their exact value is known to within several American nickels.
仅仅几片美国镍片的价值就那么不一样吗?
Just a few American nickels worth of difference?
是的
Yeah.
这些小东西是依照千克的标准定义K20来测量的
That tiny uncertainty is measured with respect to the very definition of the kilogram
那是美国的基础质量标准
using K20 – that’s the United States fundamental mass standard.
这是基于K20组合出来的已知砝码 还有很多未知的砝码
This is done by comparing combinations of known weights, starting with K20, with larger unknown weights,
逐步组合成越来越大的物体
gradually working up to larger and larger masses.
比如 一个5千克重的砝码由两个2千克和一个1千克组成
For example, here a single 5-kilogram mass is compared to two 2s and a 1.
通过这种方法 它们开始以磅为单位进行转化 从50磅的物质到500磅
At some point in this process, they convert and start working in pounds, going from 50-pound masses to 500 pounds,
接着变成2500磅 然后利用地磅达到10,000磅接着20,000
and then 2500 pounds. And then, using a scale in the floor, to reach 10,000 pounds and then 20,000,
最后是30,000磅
and finally 30,000 pounds.
这些巨大的合成砝码随后就会成为测量50,000磅的配重片
Combinations of these huge weights are then used to calibrate the 50,000-pound masses which form the weight stack.
我们必须知道 由于我们测量是矢量垂直力 它通常由引力场引发的物体垂直重力
And we have to have that, because what we scale is the vertical force vector that’s generated by these weights
我们把它的不确定性降低到0.0005%
hanging in a gravitational field. We sell that with an uncertainty attached to it of 0.0005%,
每一百万有五份 因此这意味着 我们保证每一百万磅足量的力都会得到精准测量
five parts per million, so that means at full one million pounds of applied force, we guarantee that to be accurate – if you will –
如果你把那五磅也含在内
within five pounds.
那样不仅仅意味着物质被精确的测量
Not only does that mean the masses have to be accurately calibrated,
还意味着这个区域的重力加速度也被计算在内
it also means the gravitational acceleration at this location has to be taken into account.
它比地球的标准重力稍微轻一些 所以需要增加600磅的重量
It’s actually slightly less than Earth’s standard gravity, so an additional 600 pounds are required.
另外这些物质在空气中会转移125磅来抵消浮力
Plus, the buoyant force must be counteracted, since these masses displace 125 pounds of air,
为了达到一百万磅的推力力还要再增加125磅
a further 125 pounds must be added to reach a million pounds of force.
有种疯狂的想法侵袭着我 就像 在某种程度上这个机器必须要存在
What strikes me as kind of amazing is that, like, this machine needs to exist, in a way.
当我思考比如波音客机如何测量自身的重量 我会想
When I would have thought about it, like how would Boeing measure its forces, I would have thought
好吧 它们就是 呃 被某种神秘的装置测量的 它们就是能 嗯
OK, they just, you know, calibrate a device that works up to X but then they can, you know,
一般来说 对 一般来说 你懂的 就像 对的!
generalize. Well, generalize – you know what I mean, like – Yes!
常言道“实践出真知”
There’s an axiom that says “one physical test is worth a thousand expert opinions.”
它已经在时间中一次又一次的证明了自己 尤其在世界范围的物理实验中
And that has proven itself time and again, particularly in the world of physical testing.
如果你登上了某人建造的飞机 你能接受高达10%的不确定性
If you’re getting on an airplane that somebody has built, are you willing to accept a 10% uncertainty on these numbers
或者你想让它变成不知道什么时候会降落在泥浆里的测量物吗?
or do you want it to be – the uncertainty on these measurements to be down in the mud?

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视频概述

飞机、火箭……这些大型的物体是怎么被测量出来的?

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收集自网络

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小葵酱

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与光同尘

视频来源

https://www.youtube.com/watch?v=_k9egfWvb7Y

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