题目

连词成句【1】she, to, is, school, walking________________________________________________________________________?【2】your, what, do, does, sister________________________________________________________________________?【3】my, sits, beside, sister, often, me________________________________________________________________________.【4】his, where, sleeping, is, cat ________________________________________________________________________?【5】under, there, boys, the, tree, are, two________________________________________________________________________. 如图所示，光滑细圆管轨道AB部分平直，BC部分是处于竖直平面内半径为R的半圆，C为半圆的最高点．有一质量为m，半径较管道略小的光滑的小球以水平初速度v0射入圆管． (1)若要小球从C端出来，初速度v0应满足什么条件？ (2)在小球从C端出来瞬间，对管壁压力有哪几种情况，初速度v0各应满足什么条件？