HKDSE Physics Chapter 2 Quick Outline: Newton's First Law of Motion (Inertia): An object remains at rest or in uniform velocity unless acted upon by a net force. Mass is the measure of inertia. Newton's Second Law of Motion (F=ma): The acceleration of an object is directly proportional to the net force acting on it. Covers free fall and inclined planes. Newton's Third Law of Motion (Action & Reaction): For every action force, there is an equal and opposite reaction force acting on different bodies. Connected Bodies: When objects are connected by a string, they share the same displacement, velocity, and acceleration. Learn to calculate common acceleration and internal tension.