明矾净水原理方程式

骑车人以2m/s的速度开始下坡,加速度为0.8m/s, 人骑自行车下坡,坡长l=500 m,坡高h=8 m,人和车总质量为100 kg,下坡时初速度为4 m/s,到达坡底时车速为10 m/s,g=10m/s^2.求：（1）在人不踏车的情况下,人骑自行车下坡的加速度多大（2）人骑自行车下 我要答案及理由,特别是理由!1.She said that her mother ___ for three years.A.has been dead B.has died C.had been dead D.had died2.It ___ last night,for the ground is covered with snow.A.must snow B.must be snow C.must have snowed D.can snow He does not know anything about parrots(nothing)_____________________________________________My cat is hungry ,but there is nothing to feed him in the fridge.(anything)_____________________________________________I did not see anybody in the room.(no 英语问题（英语高手们,来吧）I recall when I was young OH, I will play and always having fun with the neighbour next to me And we’ll play until the setting sun try to be The best among the others in a game call the “Spider battle” It 英语翻译1.他每天什么时候睡觉呢?2.你和你的同学在哪里做作业?3.谁想同我一起去电影院看电影?4.他正坐在哪里呢?5.那个男孩每周末下午四点都骑车去公园?到底谁对呢？ 不要脸用英语怎么说? :不要脸:英语怎么说妮?不懂才问 "给你脸不要脸"用英语怎么说? 英文期刊第几期怎么翻译日报,周刊,在英语里边,第几期,怎么翻译?比如《华尔街日报》,第几期,还有周刊,也一样吗 浏览杂志 英语怎么说 英语翻译BOSS给我一本英文杂志,想把它翻译成中文,然后可以阅读.大概有50页吧.我打算先扫描入硬盘,然后文字识别,最后用软件翻译,并手工修改,用PS替换并覆盖原版本,然后用A4双面打印出来, 看英语杂志用英语怎么说 英语阅读题 , 英语阅读,第三题, 英语阅读第一题, 一道英语阅读题 The Europeans who left their homeland in the 18th centuries and settled their homes in north America are referred to (指的是) as early settlers.Early settlers who came from the eastern parts of the present U.S.A.were used to 英语单词填空（按首字母）——初中水平Nick liked dogs very much.Each of his friends had one e_____ him.He told his mother about it and asked her to buy one for him,but she didn't agree.she was always sick at home and only her h_____ w 汉语中的〃不要脸”翻译成英语怎么说啊 骂我不要脸英语怎么说 “你们这些不要脸的!”英语怎么说? 【物理】如果迎面的风速是5m/s ,一个人迎着风骑自行车的速度也是5m/s.那么会出现什么情况?此人会静止不动,还是仅仅会速度下降,骑行更费力.为什么,最好能给出合理解释 正在行驶的列车速度是5M/S,这句话的物理意义是RT 英语翻译否则老班要K死我的（3天以内要啊）Be quick! 最新的短英语新闻,要有翻译,短,新 谁能帮我找几句英语新闻?(外加中文翻译) 英语阅读练习Do you know why different animals or pests(昆虫) have their special colors?Colors in them seem to be used mainly to protect themselves.Some birds like eating locusts(蝗虫),but birds cannot easily catch them.Why?It is because loc “默写”的英语翻译是什么貌似是e、a打头的吧反正大家发过来就对了 默写 英文怎么说"默写"这个词,英文怎么说? 这些英语曾默写1月2日,10月9日,3月5日,11月3日,6月7日,12月18日,5月20日,10月25日,7月12日,12月10日,8月22日,8月30 日,9月8日,5月19日 -小军从家到学校,以每分钟100米的速度恰好到学校,如果每分钟加快1/4,就可以提前3分钟到校,小军家到学校的距离是多少米? 不要脸!用英语怎么说