一个小球从5m高处落下,被水平地面弹回,在4m高处被接住,则小球在整个过程中(取向下为正方向)()
A.位移为9m
B.路程为-9m
C.位移为-1m
D.位移为1m
参考答案:D
阅读短文,判断正误。正确的在括号里打“√”,错误的打“×”。
Hi! I'm Helen. I'm twelve years old. Tom and Kate are my good friends. we like our school very much. It's
so beautiful. Usually I go to school on foot. Because my home is near. Tom usually goes to school by bike. His
home is far. But sometimes he goes by taxi. kate's home is far, too. She usually goes to school by bus. Because
it's cheap.
( ) 1. Helen is 11 years old.
( ) 2. Usually Helen goes to school by bike.
( ) 3. Helen's home is near.
( ) 4. Sometimes Tom goes to school by taxi.
( ) 5. Tom's home is near.
我国著名的地质学家李四光,在对东北的地质结构进行了长期、深入的调查研究后发现,松辽平原的地质结构与中亚细亚极其相似,他推断,既然中亚细亚蕴藏大量的石油,那么松辽平原很可能也蕴藏着大量石油。后来大庆油田的开发证明了李四光的推断是正确的。
以下哪项与李四光的推理方式最为相似()
A.他山之石,可以攻玉。
B.邻居买 * * 中了大奖,小张深受启发,也去买了 * * 票,结果没有中奖。
C.某乡镇领导在考察了荷兰等国的花卉市场后认为要大力发展规模经济,回来后组织全乡镇种大葱,结果导致大葱严重滞销。
D.每到炎热的夏季,许多商店腾出一大块地方卖羊毛衫、长袖衬衣、冬靴等冬令商品,进行反季节销售,结果都很有市场。小王受此启发,决定在冬季种植西瓜。
E.乌兹别克地区盛产长绒棉。新疆塔里木河流域与乌兹别克地区在日照情况、霜期长短、气温高低、降雨量等方面均相似,科研人员受其启发,将长绒棉移植到塔里木河流域,果然获得了成功。