And we're going to have q2 prime, and we're going to draw the arrows in the positive direction in these cases.
还有q2一撇,在这个例子中,我们把箭头朝正方向。
I hear this as me being in the center and this oxcart starting-- It could start at either side. It doesn't matter.
我听着这首曲子,感觉像我正站在路中央,然后牛车动了,牛车可以从任何方向开动,这没有关系
They love their country but they also know that things are going very wrong in the world.
他们热爱自己的祖国,他们同时也知道,事情正朝着不好的方向发展。
And now since it's reversible, we can run it forward or backward.
因为它是可逆的,所以可以正方向运行。
So, what this means is that when we're looking at an actual wave function, we're treating it as a wave, right, so waves can have both magnitude, but they can also have a direction, so they can be either positive or negative.
这意味着,当我们看一个波函数时,我们把它看做一个波,波不仅有幅值,还有方向,所以它们可正可负,如果。
Then you guys know, you just told me, acceleration is -9.8, We call it "minus" because it's accelerating down and up was taken to be the positive direction.
然后你们都知道,你告诉我,加速度是-9.8,我们取负号是因为加速度方向朝下,而正方向为竖直向上
This equation is telling you if you compress it, namely if x is negative, F will be then positive, because it's pushing you outwards.
这个方程告诉我们,如果压缩弹簧,即令 x 为负,F 就为正,因为推力的方向向外
Unit vector i points away from the origin in the x direction.
单位矢量 i 从原点指向 x 轴正方向
But since it is a component it can have a direction, too, so can go up l between negative l and positive l.
但因为它是个分量,它是有方向的,所以它可以,从负的l一直到正的。
j points away from the origin in the y direction.
从原点指向 y 轴正方向
By the way, I didn't tell you this but I think you know that I picked my origin to be here and measured y positively to be upwards and I called that 15 meters.
顺便说一下,虽然我没明确指出,但我想你们应该都知道,我把原点取在这里,并规定y的正方向朝上,我设把这里的高度为15米
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