Newton's laws (physics)

The three foundational principles of classical mechanics that describe how objects move and interact, formulated by Newton in the 17th century. These laws underpin virtually all everyday physics—from spring dynamics to planetary orbits—and remain extraordinarily accurate at human scales, even though they're superseded by relativistic and quantum theories at extremes.

First Law (Inertia): An object at rest stays at rest, and a moving object continues moving in a straight line unless acted upon by a force.

Second Law (Force and Acceleration): The net force on an object equals its mass times its acceleration: F = ma. This simple equation connects measurable quantities and enables prediction.

Third Law (Action-Reaction): For every force one object exerts on another, there is an equal and opposite force in return. This ensures momentum is conserved in closed systems.

Together, these laws enable modeling everything from celestial mechanics to bridge design. They were revolutionary because they unified terrestrial and heavenly motion under one coherent framework—a watershed moment in human understanding.

Related

Force, Mass, Acceleration, Momentum conservation, Classical mechanics, Orbital mechanics