It is interesting for him to study the derivative of a vector.

对他来说，研究矢量的导数是很有趣的事。

youdao

So, the definition will take effect. The acceleration is as a vector, and the acceleration vector is just the derivative of a velocity vector.

有必要对加速度给出一个严格的定义，加速度,作为一个矢量,是速度的一阶导数。

youdao

So, the velocity vector is the derivative of a position vector with respect to time.

速度向量，是位置向量关于时间的导数。

youdao