Unbalanced forces can cause an object to do three things. What are they?

Forces are considered balanced when all of the combined forces lead to no change in the motion of the object.  For example, when a book is sitting on a table, the force of gravity is pushing downward and the normal force is pushing upward with exactly the  same amount of force.  Since they are equal and opposite forces, the book does not move.

Unbalanced forces exist when there are unequal forces acting upon the object, which leads to a change in the state of motion.  Unbalanced forces can lead to a change in direction, a change in speed, or both a change in direction and in speed.