when does an object have a positive change

Balanced forces acting on an object do not change the object's position.

No, the measured weight of an object WILL change but the mass of an object will never change regardless of the gravitational force on object.

Yes, forces can change an object's motion. When a force is applied to an object, it can cause the object to accelerate, decelerate, or change direction. The change in motion is determined by the magnitude and direction of the force applied.

Force is an influence that produces a change in an object.