# Newton's Laws of Motion
Confidence: high
Last verified: 2026-05-22
Generation: ai_assisted


## TL;DR

Newton's three laws (1687, Principia) form the foundation of classical mechanics. 1st Law (inertia): object at rest stays at rest; in motion stays in motion unless acted upon by force. 2nd Law: F = ma (force equals mass times acceleration). 3rd Law: every action has equal and opposite reaction.

## Core Explanation

1st Law: seatbelt prevents you from continuing forward when car stops — your body wants to keep moving (inertia). 2nd Law: heavier objects need more force to accelerate — why trucks accelerate slower than motorcycles. 3rd Law: rocket pushes exhaust down, exhaust pushes rocket up. Newton also: law of universal gravitation (F = Gm₁m₂/r²), calculus (simultaneously with Leibniz), optics (light = particles).

## Further Reading

- [Philosophiæ Naturalis Principia Mathematica (Newton, 1687)](https://www.gutenberg.org/ebooks/28233)