When a net zero external unbalanced force is applied on the body, it is possible for the object to be travelling with a non-zero velocity. In fact, once an object comes into motion and there is a condition in which its motion is unopposed by any external force; the object will continue to remain in motion. It is necessary that the object moves at a constant velocity and in a particular direction. This can happen under the following conditions:

(a) The object should already be travelling with a uniform speed in a straight line path.

(b) There should be no change in the magnitude of speed.

(c) There should be no change in the direction of motion.

(d) The friction between the object and the ground must be zero.

(e) The air resistance on the moving object must also be zero.