question_answer 1)

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:

Yes, when external unbalanced force on an object is zero, the object can be travelling with a non-zero velocity. The necessary conditions are: (i) The object should already be moving with a uniform speed along a straight line. (ii) There should be no change in magnitude of velocity and also no change in the direction of motion. (iii) The resistance to motion due to air must be zero. (iv) The resistance to motion due to friction between the object and .the ground must be zero. If any of the four conditions stated above is not met with, the answer will be no. This is because external unbalanced force is needed for initiating the motion and also for any subsequent change (decrease/increase) in its velocity.