This is accelerating downhill, at some angle;

这个有一定角度沿斜面加速向下
that's accelerating uphill.

而那个是竖直加速向上
These are not equations which are vectors;

这些都不是矢量方程
these stand for equations along certain directions.

这些代表的是某个特定方向上的方程
This is the up/down direction here,

这是竖直方向的
and that is up the slope, down the slope direction, for that one.

而那个是沿着斜面方向的
But I think you realize if the rope is inelastic,

但我想你们考虑到了如果这根绳子是非弹性的
if this mass moves down one inch,

如果这个物体向下移一英寸
that's got to go up one inch.

那个物体就向上移一英寸
Therefore, if it goes one inch in one second,

就是说如果这个物体每秒向上一英寸
so will the other guy,

另一个也一样
they'll have the same velocity and they'll have the same acceleration.

它们有同样的速度和加速度