Here's why:

* Balanced forces: When forces are balanced, they cancel each other out. The object remains at rest or continues moving at a constant speed in a straight line (Newton's first law).

* Unbalanced forces: When forces are unbalanced, one force is stronger than the other(s). This means there's a net force acting on the object.

The net force is the *resultant* force – the single force that would produce the same effect as all the individual forces acting on the object.

Example:

Imagine you push a box with a force of 10 Newtons to the right, and your friend pushes it with a force of 5 Newtons to the left. The net force is 5 Newtons to the right (10 N - 5 N = 5 N). The box will move to the right because the unbalanced force is pushing it in that direction.

In summary: Unbalanced forces result in a net force that causes a change in the object's motion. The object will accelerate in the direction of the net force.