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问题 选择题

假设一个篮球运动员在某次投篮过程中对篮球做功为W，出手高度为h1，篮筐距地面高度为h2，球的质量为m，不计空气阻力，则篮球进筐时的动能为（　　）

A．W+mgh1-mgh2

B．mgh2-mgh1-W

C．mgh1+mgh2-W

D．W+mgh2-mgh1

答案

对于篮球来说从由静止抛出到进入篮筐的过程中有人在投篮时对它做的功和它在上升过程中重力所做的功，根据动能定理可有

W-mg（h2-h1）=EK

所以篮球到达篮筐时的动能EK=W-mg（h2-h1）=W-mgh2+mgh1

故A正确．

故选A．

判断题

《学记》中“道而弗牵，强而弗抑，开而弗达”论述了循序渐进的教学原则。( )
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阅读理解

阅读理解。

May 29th.

Dear Jenny,

     I'm sorry you're ill(病) at home and can't come to school this week, let me tell you what you have on

Monday next week.

     We have math at 8:00. It's boring, I think! Then we have English. That's interesting. I know you love

English. Next is P.E. The fourth lesson is art. That's my favorite subject! In the afternoon, we only have

two classes. We have history with Mr. Chen. He is fun but history isn't. Then at 2:00, We have science

with Miss Jones. I don't like her because she is too strict. Then we go and see a movie. It's a cartoon-Tom and Jerry. And I like it very much. In the evening, we have a party, because that day is June 1st.

                                                                                                                                    Ben.

1. Mr. Chen is their _______ teacher.

A. English

B. history

C. science  

D. P.E

2. How many classes do they have on Monday morning?

A. Three.

B. Four.    

C. Five.   

D. Seven.

3. Ben's favorite subject is_______.    

A. P.E      

B. art      

C. English      

D. math  

4. They want to see ______________in the evening.

A. a cartoon

B. a comedy  

C. a thriller      

D. an action movie

5. They have a party on _______.

A. May 29th

B. Friday

C. June 1st  

D. Saturday
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