To find the force exerted on a hanging massive rope by the ceiling, one must consider the weight distribution along the rope. The weight of the rope below point P is calculated as (W/l)*y, while the tension at point P is determined by the weight above it, given by (W/l)*(l-y). The total weight of the rope can be expressed as lzg, which is equivalent to Mg. Understanding these relationships is crucial for analyzing tension in the rope. The discussion emphasizes the importance of correctly applying these formulas to determine the forces involved.