题目

When Frida Kahlo’s paintings were on show in London, a poet described her paintings as “ a ribbon （丝带）around a bomb”. Such comments seem to suggest Kahlo had a big influence on the art world of her time. Sadly, she is actually a much bigger name today than she was during her time. Born in 1907 in a village near Mexico City , Kahlo suffered from polio（小儿麻痹症）at the age of seven. Her spine（脊柱）became bent as she grew older. Then, in 1925, her back was broken in several places in a school-bus accident. Throughout the rest of her life, the artist had many op某同学在“用单摆测定重力加速度” 的实验中进行了如下的操作： ① 用游标上有10个小格的游标卡尺测量摆球直    径如图13（甲）所示，摆球直径为______cm 。把摆球用细线悬挂在铁架台上，测量摆线长，通过计算得到摆长L。 ② 用秒表测量单摆的周期。当单摆摆动稳定且到达最低点时开始计时并记为n = 0，单摆每经过最低点记一次数，当数到n = 60时秒表的示数如图13（乙）所示，该单摆的周期是T=____s（结果保留三位有效数字）。 ③ 测量出多组周期T、摆长L数值后，画出T2—L     图象如图13（丙），此图线斜率的物理意义是 A．    B．    C．    D． ④ 与重力加速度的真实值比较，发现测量结果偏大，分析原因可能是 A．振幅偏小 B．在单摆未悬挂之前先测定其摆长 C．将摆线长当成了摆长 D．开始计时误记为n=1 ⑤ 该小组的另一同学没有使用游标卡尺也测出了重力加速度。他采用的方法是：先测出一摆线较长的单摆的振动周期T1，然后把摆线缩短适当的长度，再测出其振动周期T2。用该同学测出的物理量表达重力加速度为g=____。