This lecture covers the dynamics of mechanical systems, focusing on propeller-generator groups, wind power plants, and motor-pump units. It explains the concept of engine-machine units, movement regimes, and the equations of motion for rotating groups. The instructor discusses the training effort, torque variations, and the characteristics of receivers in mechanical systems. Additionally, the lecture explores the stability conditions of group speeds, irregularities in walking mechanisms, and the impact of disturbances on system performance.