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托福TPO-29 Lecture 4(上)

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Listen to part of a lecture in a structural engineering class.

听一段结构工程学课程。

Today let's begin to look at structural engineering in the Space Age.

今天我们开始讲太空时代的结构工程学。

Uh, new problems...new possibilities mean we can think in new ways, find radically different approaches.

新的问题......新的可能性代表着我们也能从新的角度思考,找出完全不同的方法。

So let's consider...uh, well, what would you say is the biggest obstacle today to putting structures, equipment, people ...uh, anything really, into space?

想想......你觉得今天来说,要把结构、设备、人......任何东西吧,送入太空,最大的障碍是什么?

Well, the cost, right?

成本吧?

太空时代的结构工程学.jpg

Exactly. I mean, just taking the space shuttle up and back one time is hugely expensive. Uh, why?

完全正确。我的意思是,仅仅是把太空船送出去再回来一次就已经是极度昂贵的了。为什么呢?

I guess a lot of it is for fuel, right? To...to get the rocket going fast enough.

我猜大部分(钱)花在燃料上,对吧?因为火箭的速度要足够快。

OK. Fast enough to...

好。足够快以......

To escape Earth's gravity.

以挣脱地球引力。

Good. So we are burning up an enormous amount of fuel at every launch just to get the rocket up to what's known as escape velocity.

对。我们每次发射都会燃烧掉大量的燃料,来让火箭达到所谓的“逃逸速度”。

Now, escape velocity is around 11 kilometers a second, pretty fast. But do we really have to go this fast?

逃逸速度大约在每秒11公里,这非常快。但,我们真的需要这么快吗?

Well, yeah. I mean, how else can you, um...escape?

要吧。我是指,要不然你怎么能......逃出去呢?

I mean, that's the whole point of escape velocity, right?

这是逃逸速度的全部意义所在,不是吗?

Otherwise gravity will pull you back down to the Earth.

否则引力会把你拉回地球。

Actually, that's a common misconception.

事实上这是普遍的误解。

Escape velocity is simply the speed of an object that's ...uh, let's say, shot out of a cannon, the minimum initial speed so that the object could later escape Earth's gravity on its own.

逃逸速度就是某物体的速度......这么说吧,某物体从大炮中发射出来所具有的最小初速度,这速度能让该物体之后自行挣脱地球引力。

But that's just if there's no additional force being applied.

但这种情况是没有额外外力的情况。

If you keep on supplying force to the object, keep on pushing it upward, it could pull away from Earth's gravity at any speed.

如果你持续给该物体提供动力,不断把它往前推,任何速度下它都能摆脱地球引力。

Even really slow?

哪怕它很慢?

So you're saying ...like, if you had a ladder tall enough, you could just climb into space?

你说的是......如果你有一个足够高的梯子,你能直接爬进太空?

Yeah! Uh, well, theoretically.

对。理论上来说。

I mean, I can see some practical problems with the ladder example.

我是指,我能想出梯子这个例子中一些实际应用中的问题。

Uh, like you might get just a little bit tired out after the first few thousand kilometers or so, uh, especially with all the oxygen tanks you'll have to be hauling up with you.

比如,在爬完刚开始的几千公里后,你可能会觉得有点累,特别是你还要带一大堆氧气罐一起爬上去。

No. I was thinking more along the lines of an elevator.

我的想法更偏向于电梯那方面。

Wait! You are serious?

等等!你是认真的?

Sure. An elevator. That's a new idea to most of us, but in fact it's been around for over a century.

当然,电梯。这对我们来说是个新奇的想法,但事实上这种想法已经存在超过一百年了。

重点单词   查看全部解释    
additional [ə'diʃənl]

想一想再看

adj. 附加的,另外的

 
misconception ['miskən'sepʃən]

想一想再看

n. 误解,错误想法

联想记忆
initial [i'niʃəl]

想一想再看

n. (词)首字母
adj. 开始的,最初的,

联想记忆
ladder ['lædə]

想一想再看

n. 梯子,阶梯,梯状物
n. (袜子)

 
obstacle ['ɔbstəkl]

想一想再看

n. 障碍,绊脚石

联想记忆
velocity [vi'lɔsiti]

想一想再看

n. 速度,速率,迅速

 
elevator ['eliveitə]

想一想再看

n. 电梯,飞机升降舵,斗式皮带输送机

联想记忆
radically ['rædikəli]

想一想再看

adv. 根本地,完全地,过激地

 
gravity ['græviti]

想一想再看

n. 重力,严重,庄重,严肃

联想记忆
escape [is'keip]

想一想再看

v. 逃跑,逃脱,避开
n. 逃跑,逃脱,(逃

 

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