Unbalanced/Resultant Force
Forces can be described as a push or pull that can cause an object with mass to change its velocity. This may cause an UNBALANCED FORCE.
As these two forces are acting in opposite direction, you can think of them as being equivalent to a single force. To find this, you find the difference. The result can be shown as this:
(4N – 3N = 1N)
(4N – 3N = 1N)