题目

When I was twelve years old, my father took me to see Zig Zigler. I remember sitting in that dark hall listening to Mr. Zigler   1  everyone’s spirits up to the ceiling; I left there feeling like I could do anything．When we got to the car，I   2  to my father and said, “Dad，I want to__3  people feel like that．” My father asked me what I meant．I said to him, “I want to be a   4 speaker just like Mr. Zigler,” I replied   5  ．A dream was born． Recently，I began seeking my   6  of motivating(调动积极性) others．  7  a four—year relationship with For如图所示，小球（可被视作质点）质量为m，固定在竖直平面内的圆环其最高处有一小缺口A，小缺口的直径略大于小球的直径。细绳拉着小球在圆环内绕环心O做圆周运动，小球不脱离圆轨道，圆环半径为r，细绳的长度也是r.细绳所能承受的最大张力为小球重力的3倍.用g表示重力加速度.小球在最高点A允许的最大速率和最小速率是多大？