问题 实验题

在“探究力的平行四边形定则”实验时,

(1)下列叙述正确的是__________.

A.两弹簧测力计的拉力可以同时比橡皮筋的拉力大

B.如果只有一个弹簧测力计则不能完成本实验

C.两次拉橡皮筋时,需将橡皮筋结点拉到同一位置O.这样做的目的是保证两次弹簧测力计拉力的效果相同

D.若只增大某一只弹簧测力计的拉力大小而要保证橡皮筋结点位置不变,只需调整另一只弹簧测力计拉力的大小即可(2)若两个弹簧秤的读数分为3N、4N,且两弹簧秤拉力方向的夹角为锐角,则      (选填“能”或“不能”)用一个量程为5N的弹簧秤测量出它们的合力,理由                          

答案

(1) AC(答不全的得3分,有错选的得0分)(2)不能    因为这两个力的合力大小超出了弹簧秤的量程  (评分说明:(1) 5分(2) 各2分共4分)

(1) 如果只有一个弹簧测力计可利用一根细绳代替另一个弹簧来做这个实验,利用替代法做实验,B错;若只增大某一只弹簧测力计的拉力大小而要保证橡皮筋结点位置不变,需要调整另一只弹簧测力计拉力的大小和方向,D错;(2)不能    因为这两个力的合力大小超出了弹簧秤的量程  (评分说明:(1) 5分(2) 各2分共4分)

阅读理解

BEIJING---No Car Day was first started by 34 cities in France on September22, 1998. It was started to protect the environment. By now, more than 1,000 cities around the world have had a No Car Day.

The first No Car Day in China was in Chengdu in 2001. Other cities, including Taipei, Shanghai and Wuhan, also support( 支持) the day.

In Beijing, more and more people are joining in the activity. It asks drivers to leave their cars at home for one day each month and walk or ride a bike to work. It also calls on Beijingers not to use cars on June 5 ( World Environment Day ).The slogan for the day is, “ If we drive for one less day, we can have one more nice day.”

So far more than 200,000 drivers have shown their support “ We can’t control the weather, but we can choose not to drive,” said Wu Zonghua, a car club chairman. Beijing is trying to have 238 blue sky days this year. In the first quarter of this year, Beijing only had 52 blue sky days. This was 11 days less than the number for the same period last year. Much of the dust( 灰尘 ) comes from the desert(沙漠), but cars cause most of the air pollution.(污染). We must do more for No Car Day.

小题1:There are      cities in China that support No Car Day according to the passage.

A.three

B. four

C. five

D.six小题2:The activity of No Car Day encourages Beijing drivers        .

A.not to work on No Car Day

B.to enjoy having a day off

C.leave their cars at home for repair

D.to ride a bike or walk instead of driving to work小题3:We can know from the passage that       .

A.more and more people in Beijing are joining car clubs

B.people will have one more World Environment Day each month

C.more and more people won’t drive on No Car Day in Beijing

D.more people in the world won’t drive any more

判断题