No horizontal force is necessary to maintain the motion.

Explanation:

* Newton's First Law of Motion (Law of Inertia): This law 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.

* Constant Velocity: The object moving at 2 m/s across a frictionless surface indicates that its velocity is not changing. This means the object is not accelerating.

* Acceleration and Force: Newton's Second Law of Motion tells us that acceleration (change in velocity) is directly proportional to the net force acting on an object and inversely proportional to its mass (F = ma).

Since the object is not accelerating, the net force acting on it must be zero.

Frictionless Surface: The statement that the surface is frictionless means there is no opposing force from friction to slow down the object.

Conclusion: Since there is no acceleration and no opposing forces, no horizontal force is needed to maintain the object's motion at a constant velocity of 2 m/s. The object will continue moving at that velocity indefinitely.