in the minus y direction and there is a normal force in the plus y direction and these two exactly cancel each other.

,在y的负方向,那么也有一个常力,在y的正方向,这两个力互相抵消。

youdao

x Well, we know how to compute partial w over partial x y or partial w over partial y, which measure how w changes if I move in the direction of the x axis or in the direction of the y axis.

我们知道如何计算∂w/∂,或者∂w/∂,这衡量了我在x轴,或者y轴方向上移动时，w的变化。

youdao

x but you better believe that there is one y So only when we deal with the y equations - does this acceleration come in-- not at all when we deal with the x direction.

方向上如果没有加速度，There，is，no，acceleration，in，the，x，direction,但是你最好相信,方向是有加速度的。，in，the，y，direction。,所以当我们处理y的方程时,需要考虑到加速度-,与处理x方向完全不同。

youdao

x but you better believe that there is one y So only when we deal with the y equations - does this acceleration come in-- not at all when we deal with the x direction.

方向上如果没有加速度，There，is，no，acceleration，in，the，x，direction,但是你最好相信,方向是有加速度的。，in，the，y，direction。,所以当我们处理y的方程时,需要考虑到加速度-,与处理x方向完全不同。

youdao