牛顿运动定律

牛顿运动定律是经典力学的三条基础定律，由牛顿在于1687年7月5日发表的巨著《自然哲学的数学原理》里提出。

通常的现代表述

• 第一定律：假若施加于某物体的外力为零，则该物体的运动速度不变（也称惯性定律）。
• 第二定律：施加于物体的外力等于此物体的质量与加速度的乘积（也称加速度定律）。
• 第三定律：当两个物体相互作用于对方时，彼此施加于对方的力，其大小相等、方向相反（也称作用力与反作用力定律）。

文言版

• 律一曰：静者不自动，动者不自止；动路必直，速率必均。
• 律二曰：质量加速度积与物力相侔。
• 律三曰：凡力必逆向等值而反。

拉丁语原文

• Lex. I. Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare.
• Lex. II. Mutationem motus proportionalem esse vi motrici impressæ, & fieri secundum lineam rectam qua vis illa imprimitur.
• Lex. III. Actioni contrariam semper & æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper esse æquales & in partes contrarias dirigi.

英文译文

• LAW I. Every body perseveres in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed thereon.
• LAW II. The alteration 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.
• LAW III. 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.