牛頓
英國科學家
If I have seen further it is by standing on the shoulders of Giants.
兩個物體的相互作用力總是大小相等，方向相反，同時出現(xiàn)或消失且作用于同一直線上。
To every action there is always opposed an equal reaction； or， the mutual actions of two bodies upon each other are always equal， and directed to contrary parts.
物體的加速度與所受的合外力成正比，與物體的質(zhì)量成反比。加速度的方向與合力的方向相同。
The alternation of motion is ever proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed.
如果物體處于靜止狀態(tài)或作勻速直線運動，只要沒有外力作用，物體將保持靜止狀態(tài)或勻速直線運動狀態(tài)。
Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it.