Law Of Conservation Of Linear Momentum — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Law of Conservation of Linear Momentum Applies to isolated systems where the net external force is zero. Commonly used for collisions and explosions. Newton's Second Law: F net = dp/dt. If F net = 0, then dp/dt = 0. Therefore, p (momentum) is constant over time. Alternatively, Newton's Third Law: Forces are equal and opposite (F 12 = -F 21). Impulse J = Force Delta t. Delta p 1 = -Delta p 2 implies p initial = p final. Net external force on the system must be zero. System must be inertial (or corrections applied). Non-relativistic speeds (mass is constant). Believing kinetic energy is always conserved (true only for elastic collisions). Ignoring the vector nature of velocity (signs matter). Applying it when external forces (like friction) are significant during the interval of interest.