Yes, the momentum of a system will change when a net force acts on it. This is a fundamental principle of physics known as Newton's Second Law of Motion.

Here's why:

* Momentum: Momentum is a measure of an object's mass in motion. It's calculated as momentum (p) = mass (m) x velocity (v).

* Force: A force is a push or pull that can cause a change in an object's motion (acceleration).

* Newton's Second Law: This law states that the net force acting on an object is equal to the rate of change of its momentum. In other words, Force (F) = change in momentum (Δp) / change in time (Δt).

Therefore, if a net force acts on a system, the momentum of the system will change proportionally to the force and the time it acts.

Example:

Imagine pushing a box across a floor. When you apply a force, the box accelerates (changes its velocity), meaning its momentum changes. The larger the force you apply, the faster the box accelerates, and the greater the change in momentum.

Important Note: If the net force acting on a system is zero, the momentum of the system remains constant. This is known as the law of conservation of momentum.