The resultant force is defined as:

The resultant force is indeed defined as the sum of all forces acting on an object. This definition is crucial in understanding how forces interact with one another. When multiple forces are applied to an object, each force can either add to or oppose others, resulting in a single force that effectively represents the overall influence on the object's motion. This net force determines the object's acceleration according to Newton's second law, which states that the acceleration of an object is directly proportional to the resultant force acting on it and inversely proportional to its mass.

Understanding that the resultant force is a vector quantity, which takes into account both magnitude and direction, is essential for analyzing motion. This concept helps explain why different arrangements of forces can yield different outcomes in terms of movement.