题型:问答题 如图所示,质量不计的轻质弹性杆P插入桌面上的小孔中,杆的另一端套有一质量为m的小球,今使小球在水平面内做半径为R的匀速圆周运动,角速度为ω.则下列说法正确的是(重力加速度为g) ( )A.球所受的合外力大小为B.球所受的合外力大小为C.球对杆作用力的大小为D.球对杆作用力的大小为 查看答案
题型:问答题 —May I speak to Mr Smith? —Sorry, he ____ Australia. But he ____ in two days.A. has been to; will come back B. has gone to; will be backC. has been in; would come back D. is leaving for; doesn't come back 查看答案
题型:问答题 患者,女,31岁,左侧上颌中切牙牙冠变色半年,已行根管治疗,无临床症状,患者咬合关系正常。修复开始前首要需进行的口腔检查是().A.颞下颌关节的检查B.咀嚼肌的检查C.可能与口腔疾病相关的临床综合检查D.X线片检查E.制取研究模型检查F.牙髓活力测试 查看答案