题干

如图所示,完全相同的两块长方形物块,在相同的水平地面上运动,拉力分别为F1和F2,且F1<F2.那么,所受摩擦力的大小关系为(   )

A:图(a)大于图(b)

B:图(a)等于图(b)

C:图(a)小于图(b)

D:无法确定

上一题 下一题 0.0难度 选择题 更新时间:2018-01-12 12:04:37

答案(点此获取答案解析)

B

同类题1

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Your Teen Is Falling Asleep in Class

    Teens have a busy morning schedule as they need to wake up and get moving very early in order to catch a bus and get to school by the required time. This means teens need to get their rest the night before or they will be too tired to learn anything at school. ____

    When a teen falls asleep in class, two things happen: he/she misses what is being taught and he/she loses the respect of the teacher. He/She may also receive a consequence from the school, depending on the classroom discipline policy. ____

    To prevent your teen from being sleepy in class, try these three tips:

    *Set a time for “lights out” on school nights. This is never any later than 10 p.m. and preferably 9 p.m. ____ Soft music can be on and used to help calm your teen.

    *Help your teen develop a nighttime routine that involves activities that slow them down for the end of the day. ____ Turning off the computer and disconnecting from friends and the excitement of the day an hour before bedtime will also help your teen relax.

    * ____ This will reinforce (增强) what it feels like to be rested and capable of accomplishing what he/she wants.

A.What's worse, they may even fall asleep in class.

B.Set a good example and show him/her your love for learning.

C.Taking a bath and reading are two activities that work well.

D.Point out the positives after your teen has had a good night's rest.

E.All of these things affect your teen's academic success and can be avoided.

F.“Lights out” means the computer, television, lights and cell phone should be off.

G.While your teen keeps his/her goals in line with your expectations, he/she may have his/her own goals.

同类题2

阅读下列材料:

    材料一  西递、宏村这两个传统的古村落在很大程度上仍然保持着那些在上个世纪已经消失或改变了的乡村的面貌。

布达拉宫自公元17世纪起就成为达赖喇嘛的冬宫,象征着西藏佛教和历代行政统治的中心                                            ——世界遗产委员会评价

材料二 徽州古村落(是)徽商文化的产物。……徽州一府六县的方志中,常会对徽商巨贾的资本投向有如下记载:在家乡修祠堂、建园第,重楼宏丽。

                                                                                                                                                                          ——王星明、罗刚《徽州古村落》

材料三 徽州古村落在选址布局上受着风水观念的强烈制约。“依山造屋,傍水结村”是他们基本的原则;但从风水学角度来看,具有完满的物质条件及合理功能的环境,并不意味着就是一个理想环境。人类有着自己的希冀、渴求和恐惧,而只有将这些情感,通过在创造自己的生活环境中表达出来,才构成一真正的理想环境。……徽州民居的天井营造有一个很动听的名儿,叫“四水归堂”,言天降雨露、财气,落到自家房顶,流入宅院。

                                                                                                                                                                       ——摘编自余治淮《桃花源里人家》

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