Occasionally, you'll find you need to cancel out units, because, of course, you're always doing unit analysis as you solve your problems, and sometimes you'll need to convert joules to kilogram meters square per second squared.

偶然地，你会发现需要消除单位，因为在解题时,经常要做单位分析，所以有时候需要把,焦耳换做,一千克乘以米的平方除以秒的平方。

麻省理工公开课 - 化学原理课程节选

If the units are supposed to come out in meters per second and you get seconds per meter, what do you figure the chances of that problem being right are?

因为如果单位本应该是米每秒,但你写的是秒每米，你认为这个题目,还有正确的机会吗？

麻省理工公开课 - 固态化学导论课程节选

The seconds cross out, the kilograms cross out, one of the meters crosses out from the top, so we're left with an answer in meters.

秒消掉了，千克消掉了，单位米和上面的一起约去了，所以我们得到的答案只剩下米。

麻省理工公开课 - 化学原理课程节选

It's something I throw up has an initial speed of 10 meters per second.

抛出物体的,初速度是10米/秒

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The one thing you want to keep in mind though is that Hertz does not actually mean inverse seconds, it means cycles per second. So, if you're talking about a car going so many meters per second, you can't say it's going meter Hertz, you have to say meters per second.

写成5每秒，或5赫兹,你们要记住的是赫兹,并不等于秒的倒数，它是每秒的循环数，如果你们说,一辆车一秒可以走多少米,你不能说它走了米赫兹。

麻省理工公开课 - 化学原理课程节选

A joule is a kilogram meter squared per second squared.

一个焦耳等于,一千克乘以米的平方除以秒的平方。

麻省理工公开课 - 化学原理课程节选