To calculate the slipping of an object down an inclined plane, one must analyze the forces acting on the object, including friction and gravitational forces. A free body diagram is essential for visualizing these forces, particularly the static coefficient of friction and the gravitational force acting parallel to the incline. The friction force opposes the gravitational force pulling the object down the slope. By comparing these forces, one can determine whether the object will slip or remain stationary. Understanding these principles is crucial for accurately predicting motion on inclined surfaces.