The correct answer is:
stationary objects as well as objects moving with a constant velocity
Explanation:
According to Newton's second law, when the net force on an object is zero, then it means that its acceleration is zero. In fact:
[tex]F=ma[/tex]
where F is the net force, m is the mass of the object, a is its acceleration. From this law we see that when F is zero, a (the acceleration) is also zero.
But acceleration=0 does not mean that the object is stationary: it means that the object is either stationary, or it is moving at constant velocity. So, the correct answer is
stationary objects as well as objects moving with a constant velocity
