来自《耶鲁大学开放课程：基础物理 第3集 第3集》
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which is a repulsion between charges.才知道这是电荷之间的排斥作用 -
Nowadays we know if you go into the neutron or the proton,如今我们知道 如果进入中子或者质子内部 -
there are quarks.就会发现夸克 -
There are forces between the quarks.在夸克之间存在力的作用 -
You can ask你会问 -
what the force that this quark will exert这个夸克对一段距离以外的那个夸克 -
on that quark at a certain separation.有多大的作用力 -
That was obviously not known to Newton.显然 牛顿不知道这个 -
Remember, Newton said F = ma,记住 牛顿只说 F = ma -
but didn't tell you what value F has in a given context.但却没告诉你 F 在特定条件下的值是多少 -
He just said whenever there's an acceleration,他只说过只要有加速度 -
it's going to be due to some forces就说明有力的作用