Is linear momentum of a system always conserved?

Law of conservation of momentum

According to the law of conservation of momentum, the momentum of a system is always constant if no external force acts on the system.

Explanation

1. According to the law of conservation of momentum, momentum can neither be created nor destroyed.
2. However, if external forces act on a system, the momentum is not always conserved.
3. Hence, momentum is conserved only in an isolated system.

No, linear momentum is not always conserved.