You have created the project charter but could not get it approved. Your manager and his boss asked that the project begin immediately. Which of the following is the BEST thing to do

A．Set up an integrated change control proces

B．Push to get the charter signe

C．Perform an impact analysi

D．Start work on only the critical path task

如图所示，长为R的轻绳，上端固定在O点，下端连一小球。小球接近地面，处于静止状态。现给小球一沿水平方向的初速度v₀，小球开始在竖直平面内做圆周运动。设小球到达最高点时绳突然断开。已知小球最后落在离小球最初位置2R的地面上。求：

（1）小球在最高点的速度v；

（2）小球的初速度v₀；

（3）小球在最低点时球对绳的拉力；

（4）如果细绳转过60°角时突然断开，则小球上升到最高点时的速度多大？（小球的质量为m，重力加速度为g）。