问题 填空题

重为100N的木箱放在水平地面上,至少要用22N的水平推力才能使它从原地开始滑动,木箱与地面间的最大静摩擦为______N,木箱从原地移动后,用20N的水平推力就可以使木箱继续做匀速直线运动,则木箱与地面间的动摩擦因数μ为______.

答案

由题,木箱放在水平地面上,至少要用22N的水平推力才能使开始滑动,木箱与地面间的最大静摩擦等于此时的水平推力,则木箱与地面间的最大静摩擦fm=F1=22N.当木箱做匀速直线运动时,根据平衡条件得到,滑动摩擦力f=F2=20N,木箱对地面的压力大小N=G=100N,则木箱与地面间的动摩擦因数μ=

f
N
=0.2

故答案为:22,0.2

选择题
阅读理解

阅读理解。

     How many times have you heard the expression that most people spend more time planning their vacation

than they do planning their lives? I would expand that expression by adding that most people spend more time

"thinking" about their vacation than they do thinking about what's important in their life.

     While rest and relaxation are a must in living a balanced life, it's not what we were created to do. After all,

the Master Creator took his R&R (Rest and Recreation) on the seventh day, only after six days of"definitely

directed thought."

      Wallace D. Wattles, wrote "There is no labor from which most people shrink (退缩) as they do from that

of sustained and consecutive thought; it is the hardest work in the world." And yet it is the first and primary

labor of achievement.

     My friend Mike Litman wrote an outstanding article this week. It's called "The Millionaire Composite" and

it analyzes one of the big differences between super-successful people and everyone else. He writes"I recently

visited a Real Estate Multi Millionaire Mogul. What did I see next to his desk? His vision statement, along with

a list of what he values in life - hand written.

      "A few months back, I interviewed an individual who has sold over a billion dollars worth of products on

television. He told me that he reads his life and business vision and goals daily, and that he takes time to

visualize (使看的见) exactly what he wants to create each night before falling asleep."

     What is your life's purpose or your personal mission statement? Is it written down? Do you review it and

think about it often? Is your life organized around your purpose and a set of goals that support that purpose?

     Without purpose and goals-definitely directed thought-you are like the proverbial "ship without a rudder

(舵)." There is power in your purpose and in your goals. It is the power that takes you over obstacles, the

fuel that propels (驱使) you toward the life you envision.

1. As is known to us all, _____ are a necessity in living a balanced life.

A. wealth and relaxation

B. health and wealth

C. work and rest

D. rest and relaxation

2. In the article The Millionaire Composite, ______.

A. the writer's friend is a millionaire

B. the permanent and continuous thought makes the writer's friend shrink

C. the writer's friend analyzes one of the big differences between super-successful people and everyone else

D. the writer's friend advises us to think over our work all the time

3. The underlined word it in paragraph 3 refers to ______.

A. an outstanding article

B. the permanent and continuous thought

C. the physical labor

D. a good plan

4. The writer wrote the passage mainly to tell us that ______.

A. we should think about our life's purpose and personal mission often

B. we had better learn how to plan our time

C. we should know what the life is

D. we should know how to become a successful businessman