Here's why:

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

* Net force: The net force is the overall force acting on an object. When forces are balanced, the net force is zero.

* Newton's First Law: Newton's First Law of Motion states that an object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Therefore, if balanced forces are acting on an object, the net force is zero, and the object's velocity will remain constant (either at rest or moving at a constant speed in a straight line).