An objects motion changes

only when a nonzero net force is applied to the object.

Explanation:

A net force is the sum of the unbalanced forces acting on an object. An object's motion changes only when a nonzero net force is applied to the object. When a nonzero net force is applied to an object, the object's speed and/or direction changes.

If the forces acting on the object are balanced, they will cancel each other out and will not cause the motion of the object to change.

isn't that kinetic energy