题目

What are the speakers talking about?A. Banks. B. Money. C. Cards. 答案：【答案】B【解析】W : Frank, how much money shall we take with us?M: We needn’t take much cash. Some small change and my bank card will be enough.此题为听力题，解析略。如图13所示，质量为m=1kg的小球用细线拴住，线长L=2.0m。当小球从图示位置A释放后摆到悬点的正下方的位置B时，细线恰好被拉断。若位置B距水平地面的高度h=5m，小球落地点C到O??的距离s=4m。O??点在悬点O的正下方。求： (1)细线刚被拉断时小球的速度大小； (2)细线所能承受的最大拉力