问题 计算题

汽车在出厂前要进行测试。某次测试中,先让汽车在模拟山路上以8m/s的速度行驶500s,紧接着在模拟山路上以20m/s的速度行驶100s。求:(1)该汽车在模拟上路上行驶的路程;(2)汽车在这次整个测试过程中的平均速度。

答案

(1)6000m(2)10m/s

题目分析:已知汽车行驶的速度和时间,利用公式S=vt得到行驶的路程;已知汽车前后两个过程中通过的路程和所用时间,可以得到总路程和总时间,用v=得到全程的平均速度.

(1)汽车在模拟山路上以8m/s的速度行驶的路程是S1= V1tl=8m/s×500s=4000m紧接着在模拟山路上以20m/s的速度行驶的路程是S2= V2t2=20m/s×100s=2000m该汽车在模拟上路上行驶的路程S=S1+S2=4000m+2000m=6000m

(2)汽车在这次整个测试过程中的平均速度v==

单项选择题

Generally speaking, a British is widely regarded as a quiet, shy and conservative person who is (1) only among those with whom he is acquainted. When a stranger is at present, he often seems nervous, even (2) . You have to take a commuter train any morning or evening to (3) the truth of this.

Serious-looking businessmen and women sit reading their newspapers or dozing in a corner; hardly anybody talks, since to do so would be considered quite (4) .

(5) , there is an unwritten but clearly understood code of behavior which, once broken, makes the offender immediately the object of (6) .

It has been known as a fact that a British has a (7) for the discussion of their weather and that, if given a chance, he will talk about it (8) .

Some people argue that it is because the British weather seldom (9) forecast and hence becomes a source of interest and (10) to everyone.

This may be so. (11) a British cannot have much (12) in the weathermen, who, after promising fine, sunny weather for the following day, are often proved wrong (13) a cloud over the Atlantic brings rainy weather to all districts! The man in the street seems to be as accurate — or as inaccurate — as the weathermen in his (14) .

Foreigners may be surprised at the number of references (15) weather that the British (16) to each other in the course of a single day. Very often conversational greetings are (17) by comments on the weather. “Nice day, isn’t it” “Beautiful!” may well be heard instead of “Good morning, how are you” Although the foreigner may consider this exaggerated and comic, it is (18) .pointing out that it could be used to his advantage. If he wants to start a conversation with a British but is at a loss to know (19) to begin, he could do well to mention the state of the weather. It is a safe subject which will (20) an answer from even the most reserved of the British.

17()

A.started

B.replaced

C.conducted

D.proposed

问答题 简答题