题干

汽车遇到意外情况时紧急停车要经历反应和制动两个过程,汽车在反应过程做匀速直线运动,在制动过程做变速直线运动,如图所示.某人驾驶汽车匀速直线运动的速度为72km/h,从发现情况到开始减速的反应时间为0.5s,从发现情况到汽车停止的行驶距离为38m.

上一题 下一题 0.0难度 选择题 更新时间:2014-04-10 08:40:29

答案(点此获取答案解析)

同类题2

根据短文内容,从短文后的选项中选出适当的选项补全短文,并将选项的编号字母依次填入题号后横线上。

Have you ever taken photos by using mobile phones with selfie sticks(自拍杆)? ____ 


However, a pair of US artists from New Mexico, Arie Snee and Justin Crowe believe they have invented a better one and they call it “selfie arm”.

____ It makes those people in the pictures seem to be holding hands

with a loved one.

The pair say it offers a far better experience than using a straight stick. The selfie arm makes people feel they are not alone when they take photos.

____They think their invention solves the main problem that the selfie stick has — people look alone while they are taking pictures of themselves with great interests. The product, at present, just an art project and a model conveniently provides you a welcoming arm.____The pair say they are fascinated by these new ideas.

The “selfie arm” is made of fiberglass. ____ The project that they work on shows the growing selfie stick

Phenomenon (现象) directly and the increasing need for narcissism (自恋) and Internet agreement.

A.It is lightweight and  easy-taking. 

B.Thousands of “selfie arms” have been made.

C.It seems that they are together with their friends.

D.For better or worse, they have taken the world by storm.

E.This new invention is a small, useful and cleverly-designed tool.

F.And better yet in the future, it'll talk in a friendly way and never get angry or upset.