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It's one thing to plug in all the numbers and say, "I know Newton's laws and I know how they work."
我们平时只是把数字代进公式,然后说,"我懂牛顿定律,也知道怎么使用"
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You divide and you find it's 9 and you say, "Okay, I know what to do with Newton's laws."
除一下,会得到 9,然后你说,"好了,我会用牛顿定律了"
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So, let's think qualitatively for a second about what that means or what the real meaning of that is. What that is telling us is that according to Newtonian mechanics and Coulomb's force law, is that the electron should actually plummet into the nucleus in 0.1 nanoseconds.
让我们定性的想想,这意味着什么,这告诉我们,根据牛顿力学,和库仑定律，电子,在0。1纳秒内,就会掉到原子核里面。
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In fact, I'll give an example in your own life where you will find that this law doesn't work.
其实,我可以举一个你们现实生活中的例子,它就不满足牛顿第一定律
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In fact, until we do electricity and magnetism the next semester, everything's going to be based on just the laws of Newton.
其实,在下学期学习电磁学之前,所有的内容都是基于牛顿定律的
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Suppose Newton comes to you and says, "I have this great law, but I don't want to publish it under my name.
假如牛顿对你说,"我发现了这个伟大的定律,但我不想以我的名义发表
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The point of Newton is, two things in the Law of Inertia, which one may think is trivial.
牛顿的观点是,惯性定律分两部分,可能有人觉得这种分法无关紧要
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But Newton's law is-- You see, you've got to go back and wipe out everything you know.
但牛顿定律是,如你所知的,你必须回到过去,忘掉你所知道的一切
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You have to be careful that this first law of Newton is not valid for everybody.
大家需要注意的是,牛顿第一定律并非所有情况都适用
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The first law, if you want to say, "What's the summary of all of this?"
关于牛顿第一定律,如果你要问,"它该如何概括呢"
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Your reaction may be that you've seen Newton's laws, you applied them in school.
你们的反应可能是,我已经见过牛顿定律了,以前在学校就学过
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Now, we have come to the second law, which is "the law."
现在,我们开始进入牛顿第二定律,也就是最重要的定律
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Take yourself back to 1600-whatever, whenever Newton was inventing these laws.
我们回到十七世纪,回到牛顿发现这些定律的时代
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First statement by Newton-- I don't feel like writing it down.
牛顿第一定律,我不想写出来
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I give you Newton's law and say, "Good luck."
我告诉你牛顿定律,然后说,"祝你好运"
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Newton's laws are not for everybody.
其实牛顿定律并不适用于所有情况
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We're going to talk about Newton's laws.
我们要介绍牛顿定律
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Now, I'll give you the third law.
下面我来讲牛顿第三定律
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Is one of them Newton's law?
其中一个是牛顿定律吗
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A typical problem that you may have done in your first pass at Newton's law, someone tells you a force of 36 Newtons is acting on a mass of whatever, 4 kilograms; what's the acceleration?
在你们第一次接触牛顿定律时,可能见过这么一道典型题目,告诉你,一个 36 牛的力,作用在一个物体上,4 千克吧,问加速度是多少
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That's the first law.
这就是牛顿第一定律
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We go to Newton.
根据牛顿定律
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So, just, if you can take what I'm saying for a moment right now that in fact this should collapse in this very small time frame, we have to see that there's a problem with one of these two things, either the Coulomb force law or Newtonian mechanics. So, what do you guys think is probably the issue here?
所以如果你们考虑我,开始说的这个塌缩应该,发生在很短的时间里，那么这两者之一就有问题,要么是库伦定律,要么是牛顿力学,你们觉得应该是哪个的问题？
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Maybe F = -kx should be called Newton's law?
也许应该把 F = -kx 称作牛顿定律
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Why is F = ma called Newton's law?
为什么把 F = ma 称作牛顿定律
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We'll give it a name, but by linking that T to that T, we can also figure out the same T must be exerted on this one by Newton's third law, because if this block is the only one that could be pulling this rope with T.
我们先给它命个名,把这个 T 和那个 T 联系起来,利用牛顿第三定律,我们可以知道这个 T 也一定作用在这个物体上,因为如果这个物体是唯一,受到绳子拉力 T 的物体
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