Now, what if there are 36 forces acting on the body?

如果有三十六个力作用于物体上怎么办
Which one should I use?

我应该用哪一个
I'm pulling and you're pushing and--

我在拉你在推还有
It's got to be the net force

我们要用合力
because Newton's Law connects the net force to the acceleration.

因为牛顿定律是把合力和加速度联系起来
If you and I have a tug of war

如果我们拔河
and we cancel each other out to zero

我们相互抵消使合力为零
then there's no acceleration.

那就没有加速度
So, you've got to go back to the definition;

所以你要回到定义上来
this is very, very important.

这非常非常重要
This F better be the total force.

这个 F 最好是合力
I should really use a subscript T for total,

这里我应该标个下标 T 表示全部