问题 实验题

(6分)

气垫导轨工作时,空气从导轨表面的小孔喷出,在导轨表面和滑块内表面之间形成一层薄薄的空气层,使滑块不与导轨表面直接接触,故滑块运动时受到的阻力大大减小,可以忽略不计。为了探究做功与物体动能之间的关系,在气垫导轨上放置一带有遮光片的滑块,滑块的一端与轻弹簧相接,弹簧另一端固定在气垫导轨的一端,将一光电门P固定在气垫导轨底座上适当位置(如图1),使弹簧处于自然状态时,滑块上的遮光片刚好位于光电门的挡光位置,与光电门相连的光电计时器可记录遮光片通过光电门时的挡光时间。实验步骤如下:

①用游标卡尺测量遮光片的宽度d

②在气垫导轨上适当位置标记一点A(图中未标出,AP间距离远大于d),将滑块从A点由静止释放.由光电计时器读出滑块第一次通过光电门时遮光片的挡光时间t

③利用所测数据求出滑块第一次通过光电门时的速度v

④更换劲度系数不同而自然长度相同的弹簧重复实验步骤②③,记录弹簧劲度系数及相应的速度v,如下表所示:

弹簧劲度系数k2k3k4k5k6k
v (m/s)0.711.001.221.411.581.73
v2  (m2/s2)0.501.001.491.992.492.99
v3  (m3/s3)0.361.001.822.803.945.18
(1)测量遮光片的宽度时游标卡尺读数如图2所示,读得d              m;

(2)用测量的物理量表示遮光片通过光电门时滑块的速度的表达式v              

(3)已知滑块从A点运动到光电门P处的过程中,弹簧对滑块做的功与弹簧的劲度系数成正比,根据表中记录的数据,可得出合力对滑块做的功W与滑块通过光电门时的速度v的关系是              

答案

(1)1.6210-2 

(2)

(3)Wv2成正比(或W  v2

阅读理解

阅读理解

    When many of us take a vacation, relaxing is what we want.But we usually return home tired and weak.

It doesn't have to be this way.

     Come home refreshed after an active trip!Don't be too tired!

     Active vacations are often the most relaxing of all.It's all in defining(定义) what an active vacation is.

We don't expect you to run slowly, or go backpacking.Well, we ask the vacationers who are not active

not to sit too long but to spend two to four hours a day doing things, such as walking the city streets,

exploring a nature protect, going to a zoo or biking along the ocean.

     These kinds of activities aren't just good for your physical health.They improve your mental health,

even your spiritual health.And they make vacations memorable and worthwhile.And after all, isn't that

what you want from your vacation? Here are some fresh ideas to make your vacations as pleasurable as

they are active and healthy.

     A walk at dawn or dusk is necessary.Try to make this a daily routine of life away from home, and

you will ensure yourself both physical and spiritual adding.

    Don't allow yourself to spend your entire time sitting in front of the water.Whether it is the ocean, a

swimming pool, or a tree-lined lake, make sure you get into the water for swimming or games or even

walking. Heck, merely standing in waist-high water is a good exercise, thanks to the action of the water.And you will feel so much more alive!

      Many of us spend a large piece of our vacations on the road, either getting to and from our destinations, or using the car for sightseeing.But no matter how beautiful the scenery is, great, memorable vacations

don't happen in a car seat.Don't wait for tiredness or nature's call to get you to pull over.Frequently get

out and stretch, walk, picnic, shop, visit, and have fun.It's important for your health and energy, and it

makes travelling a lot more active and interesting.

1. The writer writes the text mainly to __________.

A. introduce the relationship between vacations and health

B. tell us how to make our vacations relaxing

C. show us where we should go for our vacations

D. explain to us why we feel tired when traveling

2. What does the underlined word "refreshed" in Paragraph 2 mean?

A. Full and excited. 

B. Pleasant but tired.

C. Feeling less tired.  

D. Feeling regretted.

3. What advantage can "the activities" in Paragraph 5 bring?

A. They can improve our health as well as making us feel easy.

B. They just can keep us feel excited and confident.

C. They can bring us more chances to get out.

D. They can save us much time and make the trip meaningful.

4. In the last paragraph, the writer seems to advise us to __________.

A. go on vacation by car

B. not to spend too much time on the road

C. make a trip on foot

D. get out of the car for sightseeing

名词解释