Question

An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on the magnitude and direction of the velocity. If no, provide a reason.

Answer 1

Yes, an object may travel with a non-zero velocity even when the net external force on it is zero.
For example: A rain drop falls down with a constant velocity. The weight of the drop is balanced by the up thrust and the velocity of air. The net force on the drop is zero.
The magnitude and the direction of the velocity will not change with time when the net external force is zero.