The principle of conservation of linear momentum is a consequence of: MCQ with Answer and Explanation

Conservation of linear momentum follows from Newton's third law (action-reaction pairs) and second law. For an isolated system, internal forces cancel in pairs (third law), so net force = 0, thus dp/dt = 0 (second law), meaning momentum constant. While derivable from second law with third law, the direct foundational link is third law. Memory aid: 'Momentum conservation ⇔ no external force ⇔ internal forces cancel (third law)'. This conceptual question tests mechanics fundamentals, crucial for competitive exams. Always distinguish conservation laws: momentum (from spatial symmetry), energy (from time symmetry).