Here's why:

* Force is a vector: Force has both magnitude (how strong it is) and direction.

* Net force: The net force is the overall force acting on an object, considering the direction of each individual force.

* Balanced forces: Balanced forces are equal in magnitude but opposite in direction. They cancel each other out.

Example:

Imagine a box sitting still on a table.

* Gravity pulls the box downward.

* The table's normal force pushes the box upward.

These forces are equal in magnitude and opposite in direction, so they are balanced. The net force on the box is zero, which is why it remains at rest.

Key Point: When the net force on an object is zero, the object will either remain at rest (if it was already at rest) or continue moving at a constant velocity (if it was already in motion).