问题 计算题

(10分)两块竖直的足够长的平行板间有一匀强电场,在电场中用绝缘丝线悬一质量为0.01kg的带电小球,平衡时丝线与竖直方向成37°角,如图所示,此时小球离负板0.15m.求:

(1)若球在平衡位置时将丝线剪断,小球将做何种运动?何时碰板?

(2)若把小球提起,使丝线水平,然后释放小球,问小球经过最低点时绳的拉力多大?

答案

(1)小球做初速度为零的匀加速直线运动,t="0.2" (s)

(2)T="0.15" (N)

(1)小球做初速度为零的匀加速直线运动.(2分)

             解得t="0.2" (s)(每式1分,结果1分)

(2) 解得T="1.5mg=0.15" (N)

(每式3分,结果2分)

解答题
完形填空

Read the passage carefully. Then answer the questions or complete the statements in the fewest possible words.

In tomorrow’s offices, there will be more bosses and fewer assistants. New technologies have made clerical work so efficient that fewer workers are necessary, so one assistant may serve bosses.

Bosses in the United States are spending twice as much time resolving employee disputes as they did just a decade ago. Corporate downsizing has made workers more insecure and competitive, increasing the number of personality conflicts that managers are forced to settle.

Fighting age bias(偏见) may be a critical workplace issue of the future. As companies depend on older, more experienced workers to solve labour shortages in the next century, managers will need to overcome the view that older workers are less productive, less flexible, and more expensive.

Electronic networking will give more power to workers at the bottom of the corporate pecking order(等级排序). Computer networks allow employees to skip over chains of command and communicate directly with senior managers. The relative anonymity(匿名) of electronic communications will make low-status individuals more relaxed about expressing their points of view and offering valuable new ideas.

(Note: Answer the questions or complete the statements in NO MORE THAN ELEVEN WORDS.)

小题1:Fewer workers are necessary in the future due to

                                                                                                                                 .

小题2:Employee disputes mainly arise from the fact that

                                                                                                                                 .

小题3:What kind of view do many managers hold about older workers now?

                                                                                                                                 .

小题4:How could electronic networking give more power to low-status workers?

                                                                                                                                 .