The equation for net force (Fnet) is derived from the sum of forces in both the x and y directions, expressed as Fnet = √(EFx² + EFy²). EFx represents the total of all forces acting in the x direction, while EFy represents the total of all forces in the y direction. The discussion highlights the importance of using the Pythagorean theorem to correctly calculate the net force. An initial error was noted regarding the squaring of Fnet itself, which was clarified later. Understanding these components is essential for accurately determining net force in physics.