Now, if the current is sent one way through the read/write head the area is polarized in one direction.

如果当前通过读写头来发送指向一个方向的信息,这个区域的磁极指向某个方向。

哈佛公开课 - 计算机科学课程节选

If the current is sent in the opposite direction, the polarization is reversed.

如果当前发送一个相反的方向，磁极指向就反转。

哈佛公开课 - 计算机科学课程节选

So the minus vector is the same vector flipped over, pointing the opposite way.

因此负矢量即为同一矢量的翻转,指向相反的方向

耶鲁公开课 - 基础物理课程节选

The tangent's pointing towards the direction you are headed at that instant.

切线的方向就是,速度矢量在那个瞬时的指向

耶鲁公开课 - 基础物理课程节选

It tells you when a particle moves in a circle, it has an acceleration in a negative R direction, namely directed towards the center.

它告诉你当一个物体在圆周上运动时,它有一个在 -R 方向的加速度,也就是说是直接指向圆心的

耶鲁公开课 - 基础物理课程节选

So i and j are vectors of length one, pointing along x and y.

和 j 是模长为1的矢量,分别指向 x 轴和 y 轴方向

耶鲁公开课 - 基础物理课程节选

For most of us, gravity acts this way, defines a vertical direction very naturally and the blackboard is oriented this way, so very natural to call that x and call that y and line up our axes.

对我们多数人来说,重力作用下,很自然地确定了竖直方向,而我们的黑板又是这个指向的,所以很自然地定出 x 轴和 y 轴,并标出我们的坐标系

耶鲁公开课 - 基础物理课程节选