题目

（10分）若将弹簧也换成细线，在剪断水平细线的瞬间，小球的加速度大小和方向又会怎样？ 答案：当水平细线剪断时，连结小球的另一细线的弹力会发生突变．小球受到的合外力与绳垂直，如图所示，合外力F合＝mgsinθ，则小球的加速度a＝gsinθ，方向与绳垂直   －Marie, I have been putting an weight recently, which really disturbs me a lot ． －Yeah, I’ve noticed that．     A．Don’t be serious                  　B．Not at all．You’re still slim, of course C．It’s time you went on a diet        　D．I will care about what I eat．