题目

China and Western countries have something different in cultures about certain animals, but when it comes to pigs, we have the same idea—pigs are ugly, lazy and stupid.Just look at some Chinese sayings such as “Boiling a dead pig” and “A pig looking in the mirror is still a pig.” And in English, there are some expressions like “Eating like a pig” and “Pigs might fly.” None of them are Complimentary.However, pigs have some good qualities(品质). They are even as smart as dogs and elephants. They have good memories. And they know whether people treat them well or not.A UK cart18．在探究小车速度随时间变化规律实验中：（1）操作步骤中释放小车和接通电源的先后顺序应该是BA．先释放小车后接通电源B．先接通电源后释放小车（2）某同学获得一条点迹清楚的纸带，如图所示，已知打点计时器每隔0.02s打一个点，该同学选择了0、1、2、3、4、5、6七个计数点，每相邻两个计数点间还有四个点图中没有画出．测量数据如图所示，单位是mm．（a）根据△x=aT2（填公式）可判断小车做匀加速直线运动．（b）计算小车通过计数点3的瞬时速度为1.16m/s；小车通过计数点5的瞬时速度为1.78m/s；（保留3位有效数字）（c）小车的加速度为3.1m/s2（保留2位有效数字）