which pair of reactants are considered to be opposite
The size of the force on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs-equal and opposite action-reaction force pairs.Newton's Laws Applied to Collisions Newton's third law of motion is naturally applied to collisions between two objects.he size of the force on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs-equal and opposite action-reaction force pairs.