Net force is the vector sum of forces acting on a particle or body. The net force is a single force that replaces the effect of the original forces on the particle's motion. It gives the particle the same acceleration as all those actual forces together as described by Newton's second law of motion.
In physics, it is possible to determine the torque associated with the point of application of a net force so that it maintains the movement of jets of the object under the original system of forces. Its associated torque, the net force, becomes the resultant force and has the same effect on the rotational motion of the object as all actual forces taken together. It is possible for a system of forces to define a torque-free resultant force. In this case, the net force, when applied at the proper line of action, has the same effect on the body as all of the forces at their points of application. It is not always possible to find a torque-free resultant force.