星系外环应以可以观测到的速度被甩入太空，因为星团的质量不足以通过万有引力来束缚星系的边缘部分。

At the observed speeds, the outer galaxies should be flung out into space, since the clusters don't appear to have enough mass to keep the galaxies at their edges gravitationally bound.

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7月7号的这个炎热的下午，正好当Gonzales爬上菲尔墨外的山脉时，最可怕的事情发生了：风以48英里每小时的速度袭入，将火卷到公路上。

On the hot afternoon of July 7, just as Gonzales was creeping up the hill outside Fillmore, the worst happened: Wind gusts of 48 MPH moved in, sweeping the fire across the freeway.

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厨师用刀将大块的面团削入沸水中，以惊人的速度把面团变成了更短、更厚、更宽的面条。

To make this, the chef slashes chunks of dough in boiled water with eye-opening speed to make shorter, thicker and wider noodles.

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And in terms of equations that we use, it's sometimes easier to plug in the fact, since momentum is equal to mass times velocity.

在我们使用方程这方面，事实上有时是很容易代入的，因为动量等于质量乘以速度。

麻省理工公开课 - 化学原理课程节选

Once you've got that, one derivative will give you the velocity, then in a crunch you can eliminate t and put it into this formula.

一旦你得到了这个,求一阶导数就能得到速度,然后你可以消去t,把它代入这个式子

耶鲁公开课 - 基础物理课程节选

if I say a particle's location is i times t^2 plus j times 9t^3, for every value of time, you can put the numbers in and you can find the velocity by just taking derivatives.

一个质点的位置,i ? t^2 + j ? 9t^3,在每一个时间点,你可以把数值代入,并通过求导得到速度

耶鲁公开课 - 基础物理课程节选