Final answer:
Newton's Laws of Motion, which consist of three fundamental laws, describe how objects move in response to forces. The first law addresses inertia and uniform motion, the second defines the proportional relationship between force, mass, and acceleration, and the third law covers action-reaction pairs and the conservation of momentum in a system.
Step-by-step explanation:
Understanding Newton's Laws of Motion
Sir Isaac Newton's contributions to physics include the formulation of the three fundamental laws of motion that describe the relationship between a body and the forces acting upon it, and its motion in response to those forces. The first law, also known as the law of inertia, states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.
Newton's second law presents a quantitative description, asserting that the change of motion of a body is proportional to and in the direction of the external force acting on it. This law introduces the concept of acceleration being directly proportional to the net force and inversely proportional to the mass of the system. Finally, Newton's third law explains action-reaction pairs, stating that for every action, there is an equal and opposite reaction. This law allows us to understand the conservation of momentum in a closed system where all internal changes of momentum compensate each other, ensuring the total momentum remains unchanged.