质点沿半径为R的圆周作匀速率运动,每T秒转一圈。在2T时间间隔中,其平均速度大小与平均速率大小分别为<br>· <img src="/lqwvjeImg/dc/dc5791677f5c0692caf75401c2ee66f6.png"style="width:54px;height:18px;"> ,<img src="/lqwvjeImg/dc/dc5791677f5c0692caf75401c2ee66f6.png"style="width:54px;height:18px;"><br>· 0 ,<img src="/lqwvjeImg/dc/dc5791677f5c0692caf75401c2ee66f6.png"style="width:54px;height:18px;"><br>· 0 , 0<br>· <img src="/lqwvjeImg/dc/dc5791677f5c0692caf75401c2ee66f6.png"style="width:54px;height:18px;"> , 0.