Question

What is the meaning of net external force?

Answer 1

The net external force is the vector sum of all the forces acting on a system from the outside of the system. There may be multiple external forces acting on a body or a system but there will be only one net external force which is the result of all those external forces acting on that body or system.

The net external force is a single force that replaces the effect of the original external forces on the body's motion. It gives the body the same acceleration as all those actual external forces together as described by Newton's second law of motion.