This lecture discusses the relative motion of a puck, acting as a point mass, sliding frictionlessly on a disk rotating at a constant angular velocity. Topics covered include setting up the differential equations for the relative motion, constraints, kinematics, forces, and dynamics involved in the system. The lecture also delves into the inertial forces such as centrifugal force and Coriolis force, illustrating the complete dynamics using Newton's second law. Additionally, it explores the scalar equations of motion derived from the vectorial equation, providing insights into the absolute motion of the puck in relation to the Earth's inertial frame.