花样滑冰运动员绕通过自身的竖直轴转动，开始时两臂伸开，转动惯量为 <img src="https://static.zxtiku.com/wangke/imgs/topic/c7fa3d2d9936cae09a2343ac34cd9f97.jpg"/> ，角速度为 <img src="https://static.zxtiku.com/wangke/imgs/topic/58fe99be77c3bae8b9e4a3f240093b43.jpg"/>．然后她将两臂收回，使转动惯量减少为 <img src="https://static.zxtiku.com/wangke/imgs/topic/8695d4b5b3a1195fefecf3834d5e1f2c.jpg"/>。这时她转动的角速度变为（）。<br/> A、<img src="https://static.zxtiku.com/wangke/imgs/topic/100996afd72d46670b72591cb690f49a.jpg"/><br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/3b77084f3a6b4dbff5abdcfd4402a1b6.jpg"/><br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/053991562a14fb1a6a743d20bc7c3631.jpg"/><br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/f4de3357c59eeedf407bb36fa4868bec.jpg"/>