题型:问答题 简答题 选择合适的问句,组成对话。A. Is your birthday in July, too? B. Whose birthday is in December? C. What day is it today? D. When's your birthday?A: 1._______________________?B: It's Monday.A: 2.___________________ ?B: My birthday is in July. 3._____?A: No, my birthday is in January.B: 4.___________________________ ?A: Amy's birthday is in December. 查看答案
题型:问答题 简答题 如图所示,质量为m的小球在竖直平面内的光滑圆轨道上做圆周运动.圆半径为R,小球经过圆环最高点时刚好不脱离圆轨.则其通过最高点时( )A.小球对圆环的压力大小等于mgB.小球受到的向心力等于重力C.小球的线速度大小等于RgD.小球的向心加速度大小等于g 查看答案