That is why this says atomic number, but for most intents and purposes we can say this could be atomic mass.

那就是为什么这里说原子序数，但如果没有意图和目的,我们就说是原子质量。

麻省理工公开课 - 固态化学导论课程节选

If a photon which has no mass can behave as a particle, does it follow then an electron which has mass can behave as a wave? 1920.

如果一个没有质量的光子,能像粒子一样运动，那么它能像一个,没有质量的电子那样以波的形式运动吗。

麻省理工公开课 - 固态化学导论课程节选

So, a massless body cannot have a net force on it, because the acceleration of the rope cannot be infinite.

所以没有质量的物体不会受到力,因为绳子的加速度不可能是无穷大

耶鲁公开课 - 基础物理课程节选

And that's really neat to think about, because photons, of course, are massless particles, they have no mass, so it's neat to think about something that has no mass, but that actually does have a momentum.

而且那真的不容易想明白，因为光子，当然是无质量的粒子，它们没有质量，所以这个真的不容易想明白,一些物体没有质量，但是它们事实上确实有动量。

麻省理工公开课 - 化学原理课程节选

system is the opposite of the open system, no mass and no energy can flow through the boundary.

孤立系与开系正相反，没有质量或能量,能流过它的边界。

麻省理工公开课 - 热力学与动力学课程节选

And I have purposely made the arrow shorter to indicate that it has been slowed because we are going to argue its mass didn't change, so the only way to change its energy is to change its velocity.

我已经故意将这个箭头弄短,用来象征它变慢了,因为我们将证明它的质量没有变，只有它的能量改变了,也就是它的速度变了。

麻省理工公开课 - 固态化学导论课程节选

If a photon, which has no mass, can behave as a particle --And we know this.

如果一个没有质量的光子，像粒子一样运动--，我们知道这个。

麻省理工公开课 - 固态化学导论课程节选

We have not yet found a satisfactory answer to what's the mass of an object?

我们还没有一个令人满意的答案,物体的质量到底是多少

耶鲁公开课 - 基础物理课程节选

I mean they take up a teeny bit but essentially when we're thinking about the set up of the atom, we don't have to account for them as using up a lot of the mass we're discussing.

所以我们可以假设电子没有质量,它们占据了，非常小的一部分,所以当我们考虑,原子的构造的时候,不用考虑它们的质量。

麻省理工公开课 - 化学原理课程节选

In all these examples, this rope is assumed to be massless.

在所有这样的题目里都假设绳子没有质量

耶鲁公开课 - 基础物理课程节选