If no resultant forces or torques act on an object, both linear and angular momentum of the object remain constant.

the principle that the total linear momentum in a closed system is constant and is not affected by processes occurring inside the system

The law of conservation of momentum states that the total momentum in a closed system is always constant. This is a useful law when looking at explosions and collisions. Momentum

A fundamental law of motion, equivalent to Newton's laws: in a system of bodies (=objects), the (vector) sum of all momenta cannot change due to any internal interactions.

a law of physics that states that an object in motion will stay in motion until acted upon by an outside force; an object at rest will remain at rest until acted upon by an outside force

The principle stating that for any isolated system, linear momentum is constant with time.