If all you know is the particle is falling under the affect of gravity, that's not enough to say where the particle is, right?

如果你只知道,质点受重力作用下落,那并不足以表明物体的位移,对吧

耶鲁公开课 - 基础物理课程节选

The answer was: at any time t, the location of the particle is given by this formula.

答案是,在任意时刻 t,这个质点的位移都由这个式子给出

耶鲁公开课 - 基础物理课程节选

So, this is the most general position for a particle of constant acceleration, a.

这是一个加速度为a的匀加速质点,位移的最一般的表达式

耶鲁公开课 - 基础物理课程节选

So, the question we are going to ask is the following, "If I tell you that a particle has a constant acceleration a, can you tell me what the position x is?"

接下来要问的问题就是,如果我说某质点加速度恒为a,你能告诉我它的位移x是多少吗

耶鲁公开课 - 基础物理课程节选

If you are describing a particle with location R, the vector we use typically to locate a particle, R then R is just i times x + j times y, because you all know that's x and that's y.

如果你要描述一个位移为 R 的质点,这个矢量一般用表示质点 R 的位移,R 可表示为 i ? x + j ? y,显然你们都知道这段是 x,那段是 y

耶鲁公开课 - 基础物理课程节选