根据图示所提供的信息选择最佳答案。 ( )1.the number of the students who took part in English competitions in _______ grew faster from 2008 to 2009. A.School A B.School B C.neither school ( )2.In the English competition in_____,School B had 100 more students than School A. A.2007 B.2008 C.2009 ( )3.According to the information above,these two schools had the sane percentage of the students(12分)(1)打点计时器打点的周期,决定于【 】。A.交流电压的高低B.交流电的频率C.永久磁铁的磁性强弱D.电流的强弱(2)为减小纸带因受到摩擦而产生的误差,下列措施正确的是【 】。A.改用6 V直流电源B.电源电压越低越好C.用平整的纸带,不用皱褶的纸带D.用平整的纸带,不用皱褶的纸带(3)在“测定匀变速直线运动的加速度”的实验中,得到一条纸带如图所示,A、B、C、D、E、F为相邻的6个计数点,若相邻计数点的时间间隔为t=0.1 s,用刻度尺量得AB=1.50 cm,EF=3.10 cm,可估测小车的加速度大小为 m/s2,由此可进一步求出打下B点时小车的速度大小为 m/s。(结果保留两位有效数字)