某同学利用如图所示的实验装置验证机械能守恒定律．弧形轨道末端水平，离地面的高度为H．将钢球从轨道的不同高度h处静止释放，钢球的落点距轨道末端的水平距离为s．

（1）若轨道完全光滑，s²与h的理论关系应满足s²=______（用H、h表示）．

（2）该同学经实验测量得到一组数据，如下表所示：

（3）对比实验结果与理论计算得到的s²--h关系图线（图中已画出），自同一高度静止释放的钢球，水平抛出的速率______ （填“小于”或“大于”）理论值．

（4）从s²--h关系图线中分析得出钢球水平抛出的速率差十分显著，你认为造成上述偏差的可能原因是______．

What does it mean to say that we live in a world of persuasion? It means that we live among competing interests. Your roommate’s need to study for an exam may take priority over pizza. Your instructor may have good reasons not to change your grade. And the object of your romantic/inter­est may have other choices.

In such a world, persuasion is the art of getting others to give fair and favorable consideration to our points of view. When we persuade, we want to influence how others believe and behave. We may not always prevail — other points of view may be more persuasive, depending on the listener, the situ­ation, and the merit of the case. But when we practice the art of persuasion, we try to ensure that our position receives the attention it deserves.

Some people, however, object to the very idea of persuasion. They may regard it as an unwelcome interruption into their lives. Just the opposite, we believe that persuasion is unavoidable — to live is to persuade. Persuasion may be ethical or unethical, selfless or selfish, inspiring or degrad­ing. Persuaders may enlighten our mind or prey on our vulnerability. Ethical persuasion, however, calls on sound reasoning and is sensitive to the feelings and needs of listeners. Such persuasion can help us apply the wisdom of the past to the decisions we now must make. Therefore, the most basic part of edu­cation is learning to resist the one kind of persuasion and to encourage and practice the other.

Beyond its personal importance to us, persuasion is necessary to society. The right to persuade and be persuaded is the bedrock of the American political system, guaranteed by the First Amendment to the Constitution.

小题1:According to the passage, persuasion means ________.

A．changing others’ points of view

B．exercising power over other people

C．getting other people to consider your point of view

D．getting people to agree with you and do what you want小题2:The underlined word in the second paragraph “prevail” means________.

A．win

B．fail

C．speak

D．listen小题3:The passage states that some people object to persuasion because they think it is ________.

A．a danger to society

B．difficult to do well

C．unwelcome behavior

D．never successful小题4:The passage mainly discusses ________.

A．how people persuade

B．why people persuade

C．that persuasion is both good and bad

D．that persuasion is important and it is all around us