问题 问答题 简答题

制动力和牵引力各是怎样产生的?其大小、方向和作用点如何?

答案

参考答案:

制动力是车辆在刹车时为克服车辆的惯性力而在路面与车辆之间发生的滑动摩阻力。牵引力是车辆起动时为提供牵引力而在路面与车辆之间发生的滑动摩阻力。当着力在桥面以上1.2米处,在计算墩台时可移至支座中心或滑动支座、橡胶支座、摆动支座的底座面上;计算钢构桥、拱桥时,可移至桥面上,但不计因移动而产生的竖向力和力矩。

阅读理解

(C)

Bali is a tiny island that is part of Indonesia(印度尼西亚) today. It is a pretty island that has many mountains and a pleasant climate. For a long time, Bali was cut off from much of the world.

The people of Bali were happy and had a peaceful life. They were not allowed to fight. At one time there had been terrible wars on Bali. Then the people decided it was wrong to fight or have wars. They made rules to keep apart those people who wanted to fight.

Bali was divided into seven small kingdoms. The land around each kingdom was kept empty, and no one lived there. Since the kingdoms did not share the same borders(边界), the people could not fight about them.

On Bali, even children were not allowed to fight. If two children started a fight over a toy, someone separated them. When two boys argued, they would agree not to speak to each other. Sometimes they did not talk together for months; this gave the boys a chance to forget their anger.

Families who were angry with each other also promised not to speak. Their promise was written down, and the whole village knew about it. If they broke their promise, they had to offer gifts to their gods.

49. Bali is an island belonging to ________.

A. Europe        B. Africa         C. Asia         D. America

50. The people of Bali ______.

A. lived a happy and peaceful life

B. fought for a long time

C. is cut off from much of the world

D. quarreled about their borders

51. How did the people of Bali prevent fighting from breaking out?

A. They shared the same borders.            

B. The island was divided into seven kingdoms.

C. They made strict rules to punish those who wanted to fight. 

D. Land was kept empty around each kingdom and no one lived there.

52. Which of the following is not true according to the passage?

A. Bali is a beautiful island with many mountains and nice weather.

B. People had to offer gifts to the villagers if they broke their promise.

C. At one time there were terrible wars on the island.

D. You’ll hardly see children fighting on the island.

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