The amount of force needed to keep a 10 kg box moving at a constant speed of 0.4 m/s on frictionless ice is *
ON,
0.04N
40 N
1.4 N

ON

Explanation:

Frictional force is a force that opposes the motion of body. It is because of friction that motion can be controlled and even walking is made possible.

Now, on a frictionless surface, there is no opposition to motion. Therefore, to keep the body moving there is no force required.