Explanation:
An unbalanced force is necessary for an object to be accelerated. The following points explain why it is so:

Definition of unbalanced force:
An unbalanced force is a net force that is not equal to zero. It means that the forces acting on an object are not balanced, and therefore, there is a resultant force that causes a change in the object's motion.

Newton's second law of motion:
Newton's second law of motion states that the acceleration of an object is directly proportional to the force applied to it and inversely proportional to its mass. It can be mathematically represented as F=ma, where F is the force applied, m is the mass of the object, and a is the acceleration produced.

Relation between force and acceleration:
From Newton's second law of motion, it is clear that a force is necessary to produce acceleration in an object. Without a force, an object cannot change its state of motion. The direction of the force determines the direction of acceleration.

Relation between balanced force and motion:
When the forces acting on an object are balanced, the net force is zero, and the object remains at rest or moves with a constant velocity. In this case, there is no acceleration produced.

Relation between unbalanced force and motion:
When the forces acting on an object are unbalanced, the net force is not zero, and the object undergoes acceleration. The acceleration produced depends on the magnitude and direction of the net force.

Conclusion:
Hence, we can conclude that an unbalanced force is necessary for an object to be accelerated. Without a net force, there is no change in the object's motion, and it remains at rest or moves with a constant velocity.

If it is unbalanced then velocity will increase or decrease so it is accelerated