-Could I bother you for a moment?I need someone to copy this file for me.

-      .I need to do some copies too and I can copy them together. [ ]

A.Sorry,but I can’t

B.You are welcome

C.That’s no trouble at all

D.Don’t say so

如图所示，小球Q在竖直平面内做匀速圆周运动，半径为r，当球Q运动到与O在同一水平线上时，有另一小球P在距圆周最高点为h处开始自由下落．要使两球在圆周最高点处相碰，Q球的角速度ω应满足什么条件？