题目

如图是用以说明向心力和质量、半径之间关系的仪器，球P和Q可以在光滑杆上无摩擦地滑动，两球之间用一条轻绳连接，ｍP＝2ｍＱ，当整个装置以ω匀速旋转时，两球离转轴的距离保持不变，则此时                                   A．两球受到的向心力大小相等    B．P球受到的向心力大于Q球受到的向心力    C．ｒＰ一定等于ｒＱ／2             D．当ω增大时，Q球将向外运动Students are required to _______ down what the teachers teach in class. Which of the following is wrong?A．setB．putC．writeD．make