If the net force on an object is zero, what is the acceleration?

The net force acting on the body is zero, the acceleration acting on the object is also zero.  

Explanation:

Let the two equal and opposite forces acts on an object be, f and f'

The net force acting on the object is given by the relation,

The net force is given by the resultant vector,

                                (∵ θ = 180)

                             F = f - f'    

Since the magnitude of the forces are equal,

                            F = 0

Hence, the net force acting on the body is zero, the acceleration acting on the object is also zero.                        

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