The unit vector in the X direction.

X方向上的单位向量。

Since I had and you had, are both unit vectors projecting I hat onto the line, passing through you hat.

因为我和你都是 都是单位向量投影到直线上 穿过你。

So when you write 2i, for example, you're just saying: take the unit vector i and make it twice as long.

因此，例如，当我们编写 2i 时，它会说： 我们取单位向量 i 并使其长度增加一倍。

I had the unit vector in the Y direction, j Hat, and a new guy the unifector in the Z direction, called k Hat.

我有Y方向的单位向量 j帽 还有一个Z方向的单位向量 叫做k帽。

This is why taking the dot product with a univector can beinterpreted as projecting a vector onto the span of that unit vector and taking the length.

这就是为什么与一个单位向量做点积可以解释为将一个向量投影到这个单位向量张成的空间上 然后求长度。

Yeah, Coulomb's law gives the electrostatic force  as the Coulomb constant times charge 1 times charge 2 all divided by the square of the distance  between centers of charge all times unit vector r.

是的，库仑定律给出的静电力等于库仑常数乘以电荷 1 乘以电荷 2 除以电荷中心之间距离的平方乘以单位矢量 r。

This is why the dot product with a non unit vector can be interpreted as 1st projecting onto that vector, then scaling up the length of that projection by the length of the vector.

这就是为什么与非单位向量的点积可以解释为首先投影到该向量上 然后将该投影的长度乘以该向量的长度。