题目

A qualified doctor who rarely practiced but instead devoted his life to writing. He once said: “Medicine is my lawful wife, and literature is my lover.” Russian writer Anton Pavlovich Chekhov, was a great playwright and one of the masters of the modern short story.When Chekhov entered the Moscow University Medical School in 1879, he started to publish hundreds of comic short stories to support his family. After he graduated, he wrote regularly for a local daily newspaper.As a writer he was extremely fast, often producing a short story in an hour or less. Chekhov’s medical and scienc5．如图所示是某次研究匀变速直线运动实验中得到的一条纸带，其中A、B、C、D、E是计数点（每打5个点取一个计数点），距离如图，其中L1=3.07cm，L2=12.38cm，L3=27.87cm，L4=49.62cm．所用交流电的频率为50hz，则纸带上相邻两点之间的时间间隔为：0.02s，相邻两个计数点之间的时间间隔为：0.1s，打D点时小车的速度为1.86m/s；加速度为6.22m/s2．（计算结果均保留三位有效数字）