Question

    How Soccer Can Help Us Understand Physics

Sports provide a great way to understand some concepts(概念) in physics. Physics, after all is the study of matter, motion(运动), force, and energy. And since sports like soccer, swimming and cycling involve bodies moving through space, they  can help us understand how the principles of physics work.

Imagine that you're looking at a soccer hall on a grassy field. If you do nothing to the hall, it will stay motionless on the grass. If you kick the ball, it will roll along the grass before coming to rest again. Pretty simple , right?

For thousands of years, though, people thought that objects like this soccer ball come to rest because they have a natural tendency to stop. It took a famous physicist by the name of Sir Isaac Newton, who lived in the 1600s, to prove that this was not exactly correct.

Newton suggested that objects like the soccer ball have a natural tendency to keep moving. The only reason they stop, he believed is because an unbalanced force acts on them. By an unbalanced force, Newton meant the force applied to the soccer ball by its environment. When kicked the surface of the ball travels over the grass, creating friction(摩擦力).The taller the grass, and the rougher the surface of the ball, the more friction is created.  And the more friction that exists between the ball and the grass, the less it will travel after being kicked.

Now, imagine that there is no grass. Instead. the ball is resting on a frozen lake. When you kick the ball on the ice, the ball will go much farther than it would have on the grass. This is because ice provides a lot less friction than the grass.

Even so, ice does cause some friction. The ball's interaction with the frozen water crystals on the surface of the lake eventually causes it to come to rest again. But now imagine that instead of ice, the ball is in a place where there's no friction at all. The ball is floating in a vacuum.  If you remove friction entirely, kicking the soccer ball would cause it to keep going and going at the same speed, until some force caused it to slow down and stop. To paraphrase Sir Isaac Newton, a soccer ball on the grass will stay where it is unless acted on by a force. Similarly, once you kick the ball, it will remain in motion unless acted on by force. This, in so many words, is known as Newton's First Law of Motion.

1.According to the passage, once an object like a soccer ball is in motion, it has a natural tendency to          .

A.stop B.slow down C.keep moving D.change direction

2.What does the writer explain in the passage?

A.The idea of motion, using sports as examples.

B.The force of friction, using music as examples.

C.The sport of soccer, using examples of teams and players.

D.The importance of understanding the concepts in physics.

3.What does the underlined word" tendency" mean?

A.A very small chance of something happening.

B.A fifty-fifty chance of something happening.

C.The way something normally behaves or acts.

D.The fear of doing something or acting in a certain way.

4.The passage is mainly about             .

A.the motion of objects B.the life of Sir Isaac Newton

C.why we have to learn physics D.why we kick the ball on a grassy land

Answer

1.C

2.A

3.C

4.A

【解析】

本文是一篇说明文。文章主要介绍了体育能够帮助我们理解一些物理学概念，文章主要以足球举例，向我们介绍了物理学中摩擦力对运动的影响。

1.细节理解题。根据“Newton suggested that … to keep moving.”可知，处于运动中的物体有一直运动下去的自然趋势。故选C。

2.推理判断题。通读全文可知，本文用草地上的球和结冰湖面上的球为例，解释了“运动”这个物理概念。故选A。

3.词义猜测题。含有划线单词的句子含义是“虽然千百年以来，人们认为像足球这类的物体停止移动是因为他们有一个停下来的自然趋势”，所以，划线单词tendency的含义是“趋势”；某物能发生非常小的机会，A错误；某物能发生的对半机会B错误；某物正常的表现或动作的方式，C正确，以一定方式做某事或行动的担忧，D错误。故选C。

4.主旨大意题。本文主要讲述在不同场地的情况下足球有不同运动状态，从而解释了物理中“运动”这一概念，所以本文是关于物体的运动。故选A。