问题 填空题

如图,物体A重20N,滑轮重1N,绳重不计,弹簧测力计示数为25N,则物体B重____N

答案

 12N

 

首先除掉滑轮的重,这样示数为24N,因为测力计接的是定滑轮,所以两根绳子平分了测力计的示数,再加上B没有与地面接触,所以B的重力为12N2.这里若说的明白点,应为A和B对弹簧测力计的力为24牛,而不应该说为AB共重24牛。再根据绳子两端的力是相等的,可以得知B对弹簧测力计的力为12牛。3.   对B受力分析,向上绳子的拉力和B向下的重力平衡,即F=Gb

对滑轮受力分析,向下两段绳子,即两个拉力F,,向下滑轮的重力G轮;向上测力计处绳子的拉力,即F示

则F+F+G轮=F示,2Gb+1N=25N所以B的重力Gb=12N4.   可以这样分析,用大小为G(b)的力匀速提起物体A。

弹簧测力计测的力为G(b)+GA+1=25,所以G(b)+GA=24

因为定滑轮不省力且物体处于平衡,所以为12N。

阅读理解

Directions: The following people are going to take part in job interviews. Match the interviews (marked with A, B, C, D, E and F) with the people so that they can have a greater chance of being employed. There is one extra paragraph that you don’t need.

61. Tom is a university student graduating soon. He is smart, swift and quick-minded. He is fond of challenges. He can react to sudden changes very well.

62. Mary is a graduate who often can communicate and cooperate with others well and can make friends easily.

63. Tim is a hardworking person. He has done several jobs but still hasn’t found his favorite. Every time before he goes for an interview, he’ll make full preparations as to what interviewers may ask about him.

64. Helen has worked in an advertising company for 8 years before and now she is considering finding a job in a bigger advertising company. She is a talented woman and possesses outstanding skills.

65. Mike is a brave and honest person. He often says what’s in the mind. He has many true friends.

A

You’ll be asked a lot of questions concerning a wide variety of subjects. For example, you will be asked about the political affairs to see whether you keep an eye on the things happening at home and abroad. Of course, you should also know about the company itself very well—the basic information, the policy, the market, and the potential.

B

You may be interviewed with one or two other interviewees. The interviewer may ask you to solve problems which require you and your partner to work together. It’s as important to lead as to listen. So, team spirit matters.

C

The interviewer explores certain predetermined areas using questions which have been written in advance. You may be required to list your past experience, skills and personality. Your experience and skills are compared to specific job tasks to see whether you are fit for the job.

D

The interviewer intentionally attempts to upset you to see how you react under pressure. You may be asked questions that make you uncomfortable or you may be interrupted when you are speaking. At those times, your quick responses count.

E

In some job interviews, you will be asked about your social relationship. Sometimes, the interviewer will even ask you how much hard liquor (酒) you can drink. Just keep to the fact, or you’ll suffer later.

F

Situations are set up which simulate (copy) common problems you may meet with on the job. Your responses to these situations are measured against predetermined standards. The way of dealing with the problem really matters. The interviewers can determine whether you have the basic qualifications for  the job.

判断题