Paper 3 · Kinematics and Dynamics
How is the principle of conservation of momentum linked to Newton's third law?
AThe heavier body always exerts the larger reaction force on impact.
BMomentum conservation replaces Newton's third law in a collision.
CNewton's third law only applies to elastic collisions, not general ones.
DEqual, opposite reaction forces act for the same contact time.
Explanation: Newton's third law gives each colliding body an equal and opposite force for the same time of contact, so the impulses (changes in momentum) are equal and opposite, which is exactly what conservation of momentum requires.
Derived from ZIMSEC Physics Paper 3, November 2002, Q1