話說物有『牽一髮 而動全身』者，用之於『剛體』適切矣！若問為什麼『角速度』不如『線速度』容易想像乎？蓋僅知『歐拉角 』，尚且不知將如何運用之也！！

特介紹『歐拉盤』物理文本今說以明之呦︰

The Rolling Motion of a Disk on a Horizontal Plane

Recent interest in the old problem of the motion of a coin spinning on a tabletop has focused on mechanisms of dissipation of energy as the angle alpha of the coin to the table decreases, while the angular velocity Omega of the point of contact increases. Following a review of the general equations of motion of a thin disk rolling without slipping on a horizontal surface, we present results of simple experiment on the time dependence of the motion that indicate the dominant dissipative power loss to be proportional to the Omega^2 up to and including the last observable cycle.

 

倘若深入『運動學』名目所說事，察其與觀察者參考系之關係︰

 

自能悠遊

 

古代習題中哩。