When proving conservation of linear momentum for an isolated system of two bodies
PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
When proving conservation of linear momentum for an isolated system of two bodies, the internal forces between them are not included in the net external force because
(a) They are negligible compared to external gravitational forces.
(b) They are equal in magnitude and opposite in direction, acting on the same body.
(c) They are equal in magnitude and opposite in direction, acting on different bodies.
(d) They vanish in the centre-of-mass frame, so they do not contribute to the net external force.