Question

The law of conservation of momentum states that the total momentum of a system _____.

-increases
-decreases
-remains constant

Answer 1

The law of conservation of momentum states that the total momentum of a group of objects does not change unless outside forces act on the objects.

Answer 2

The correct answer is remains constant.

The law of conservation of momentum can be stated as in an isolated system  when any collision between two bodies takes place then the the total momentum remains constant. This law has been derived from the Newton's law of motion. The collision of body transfers its energy from body A to another body B.

Hence, in this way the total momentum remains constant.