空中转体和空翻是跳板跳水运动员经常要作的基本动作,而角动量守恒是支配包括空翻和转体在内的一切动作的基本物理原理。那末,为什么运动员可以在空中作转体和空翻动作而又不违反角动量定律呢? 在空翻动作中,运动员的脑袋朝下身体作空翻,仿佛绕着一根从左向右并通过其腰部的轴作旋转,如图1所示。在转体动作中,运动员在空中象纺锤或舞蹈演员那样旋转,就象绕着一根从头部到脚尖的轴作旋转 Aerial swivel and flip flutter are the basic actions that springboard-diving athletes often make, and the conservation of angular momentum is the basic physical principle that governs all actions, including flip and swivel. So why do athletes make swings and flips in the air without violating the law of angular momentum? In flip flops, the athlete’s head flips his head downwards as if looking around from left to right and through his waist Shaft rotation, shown in Figure 1. In swivel movements, an athlete rotates in the air like a spindle or dancer, as if rotating around a shaft from head to toe