SEVERAL KINETIC ENERGY THEOREM FORMULAS OF COMPONENT MOTIONS OF PARTICLES AND THEIR APPLICATION IN A COLLEGE ENTRANCE EXAMINATION QUESTION

This paper first proves several fractional forms of the kinetic energy theorem for particles in Cartesian and cylindrical coordinate systems, termed the kinetic energy theorem equations for translational and rotational motions, along with orthogonal superposition rules for work. Then, applying the knowledge of conservation of axial momentum moment, a conventional solution for the 11th question of the 2024 Jiangsu Provincial Physics College Entrance Examination is given, and a trend chart of the angle θ changing with the length l of the diagonal rope both in the question's diagram is made. Finally, by applying the so-called formula for the kinetic energy theorem of component motion that has been proven in the cylindrical coordinate system, it is gradually inferred approximately within the scope of middle school physics knowledge that options (B), (A), and (D) of the question are all incorrect. The content of the paper can provide useful supplements for mechanics related content in universities, as well as reference for physics teaching in universities and middle schools.