At any point on the graph you can take the derivative, which will be tangent to the curve at each point, and its numerical value will be what you can call the instantaneous velocity of that point and you can take the derivative over the derivative and call it the acceleration.

在图上的任意一点,你可以进行求导,得到曲线上每一点的切线斜率,所得到的数值,即为该点处的瞬时速度,然后你再求一次导,得出它的加速度

耶鲁公开课 - 基础物理课程节选

You see an object in motion, you find a and you give a a certain numerical value, 10 meters per second squared.

你看到一个物体在运动,你会发现它的 a,然后给 a 赋值,10 米每秒平方

耶鲁公开课 - 基础物理课程节选