The discussion centers on the role of the normal force (N) in the motion of a falling and sliding stick, specifically regarding its effect on the center of mass (CoM). Participants argue that N is necessary to prevent the stick from free-falling and to facilitate its rotation about the pivot, as it provides the upward force required to counteract gravity (mg). The conversation highlights the distinction between translational and rotational motion, emphasizing that while the stick rotates, its CoM still experiences vertical acceleration due to the net forces acting on it. Additionally, the dynamics of the stick are analyzed through the lens of torque and the rigid body concept, illustrating how internal forces distribute along the stick while external forces dictate its overall motion. Ultimately, understanding the interplay between these forces is crucial for accurately modeling the stick's behavior.