We all know that in a falling elevator, you definitely do not escape the pull of gravity.

我们都知道在一个下坠的电梯里,你当然还是会受到重力的

耶鲁公开课 - 基础物理课程节选

It knows that this particle happened to have a height of 15, at the time of 0, and a velocity of 10, and it is falling under gravity with an acceleration of -10.

这个质点恰好处在高度为15的地方,零时刻,初速为10,并在重力作用下以-10的加速度下坠

耶鲁公开课 - 基础物理课程节选