Plain English Meaning
Three rules from Isaac Newton that explain how things move. First: things keep doing what they're doing unless something pushes or pulls them. Second: how fast something speeds up depends on how hard you push it and how heavy it is. Third: every push creates an equal push back the other way. These rules explain why aircraft fly the way they do.
Full Definition
Three foundational principles of classical mechanics, formulated by Sir Isaac Newton, that describe the relationship between an object and the forces acting on it. The First Law (Inertia) states that an object at rest remains at rest, and an object in motion continues in motion at constant velocity in a straight line, unless acted upon by an external force. The Second Law states that the force acting on an object equals its mass multiplied by its acceleration (F = ma). The Third Law states that for every action there is an equal and opposite reaction. Together, these laws describe how aircraft accelerate, , change direction, and respond to the forces of , , , and .