Force And Laws Of Motion – Solutions

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.

Solution:

When an object experiences a net zero external unbalanced force, its acceleration (a) is zero as F = ma and ‘m’ (which is the mass of an object) cannot be zero. Acceleration is the rate of change in velocity. Zero acceleration implies zero change in velocity. Thus, there is no change in velocity. This implies that if the velocity of the object is zero, it remains constant. This implies that the magnitude and direction of velocity of the object remain constant. Thus, for an object undergoing net zero external unbalanced force, it is possible for it to be travelling with a non-zero velocity. In that case, the direction and magnitude of velocity of the object need to remain the same.