The stuff that people tend to add sometimes is to keep drawing the 10 Newtons that's acting on that.
有人经常凭空添加的力,总是把这个 10 牛的力硬加在这个物体上
By the way, when I say there's 10 Newtons acting this way, you might say, "What about gravity? What about the table?"
顺便提一下我说有 10 牛的作用力,你也许会问,"那重力呢,桌子对它的力呢"
Here I got 3 kg and I got 2 kg and I'm pushing with 10 Newtons and I want to know what happens.
一个物体 3 千克,另一个 2 千克,现在我用 10 牛的力推它,我想知道接下来会怎样
That's, in turn, because this guy's being pushed by the 10 Newtons, but that's not your problem.
反过来,因为这个物体被 10 牛的力推着,但和你没有关系
It's the 10 Newtons acting on it, because I know the 10 Newton is pushing me and I'm going to feel it even if I'm here.
他们认为这 10 牛的力作用在了物体上,因为这个力在推着物体前进,物体能感觉到的,即使没有直接接触
That is 6 Newtons divided by 3 kg is also an acceleration of 2.
即,6 牛除以 3 千克同样得到加速度是 2
Here is some object, it's 5 kilograms and I apply 10 Newtons.
这有一个物体,5 千克,我对它施加 10 牛的力
I got 2 kg and I pull this guy with 10 Newtons.
还有一个 2 千克的物体,我用 10 牛的力来拉它
Newtons acting on 2 kg, gives you an acceleration of 2.
牛的力作用在 2 千克的物体上,那么其加速度大小就是 2
How do we know 10 Newtons is acting?
我们怎么知道是作用力是 10 牛呢
So, tension on the rope is 6 Newtons.
所以绳子的张力是 6 牛
They add to that the 10 Newtons.
他们加上了这个 10 牛的力
A typical problem that you may have done in your first pass at Newton's law, someone tells you a force of 36 Newtons is acting on a mass of whatever, 4 kilograms; what's the acceleration?
在你们第一次接触牛顿定律时,可能见过这么一道典型题目,告诉你,一个 36 牛的力,作用在一个物体上,4 千克吧,问加速度是多少
If your plan is to accelerate a 3 kg mass with an acceleration of 2 meters per second, you better have a rope that can furnish that force and it can take the tension of 6 Newtons.
如果你想用 2 米每秒平方的加速度,去拉一个 3 千克的物体,那么你就需要一根能提供拉力的绳子,并且它能够承受 6 牛的张力
the ropes will be pulling the block with T in the other direction, then I got 10 Newtons here.
绳子也会对另一物体施加方向相反的拉力 T,于是我知道这里是 10 牛顿
Once you got a = 2, you can go back and realize here that f = 4, so you got really 4 Newtons.
一旦你算出 a = 2,你可以回到上面来,求出 f = 4,所以实际上这个力有 4 牛
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