it's actually not a force, it is a property of matter. The property is call inertia.
A force that maintains motion is called an external force. This force is responsible for overcoming any resistance or friction that may try to stop or slow down an object in motion. It keeps the object moving at a constant velocity.
It could be called superfluous. No force is necessary to maintain motion.
The force that maintains motion is inertia. Inertia is the tendency of an object to resist changes in its velocity. An object in motion will continue moving at a constant velocity unless acted upon by an external force.
First
There is no force that maintains motion by itself. Motion is maintained by Newton's Law, that objects in motion tend to stay in motion. Forces can act to stop the motion, such as the force from friction, in which case some other force, such as the force provided by a car's engine, is what keeps the car from slowing down and stopping. But, in the absence of forces acting against motion, such as friction, an object will remain in motion with no forces acting on it.
Air resistance.
A force that opposes the motion of an object is called a frictional force. This force acts in the opposite direction of the object's motion, creating resistance and slowing down its movement.
The force on Earth that always opposes the motion of a body when it is in motion is called friction.
The force that opposes motion when moving objects over a surface is called friction
an unbalanced force.
work
Inertia