when two force act in appropriate direction on an object, then any one of the following will happen
(i) If two forces of equal strength act on an object in opposite directions, the forces will cancel, resulting in a net force of zero and no movement.
(ii) When two unequal forces act in opposite directions on an object, the net force is the difference of the two forces. Unbalanced forces cause a change in motion, speed, and/or direction.
(iii) When two forces act in the same direction on an object, the net force is equal to the sum of the two forces.