问题 填空题

小球从空中自由下落,与水平地面相碰后弹到空中某高度,其速度--时间图象如图所示,则由图可知(g=10m/s2

(1)小球下落的最大速度为______

(2)第一次反弹初速度的大小为______

(3)小球下落的最大高度______

(4)小球能弹起的最大高度______.

答案

由图象可知:前0.5s内物体自由下落,后0.3s物体反弹,小球下落的最大速度5m/s,第一次反弹初速度的大小为3m/s.

根据v-t图象中速度图象与时间轴围成的面积表示位移可得:小球下落的高度为:h=1.25m

小球能弹起的最大高度为:h=0.45m

故答案为:5m/s,3m/s,1.25m,0.45m.

阅读理解

阅读理解。

     Li Ping gets up early on weekdays(工作日), because he must go to school before 7:30 .

On Saturday and Sunday, he doesn't go to school,so he must not get up early. He goes to

the Drawing Club at 9:00 on Saturday mornings. He usually goes to the bookshop on

Saturday afternoons, and after supper he watches TV until(直到) midnight.

     He doesn't get up early on Sundays. Li Ping 's parents both work on Sundays. Li Ping

always watches TV after he gets up. Then he usually goes to KFC to have a hamburger

and some juice for lunch. After that, he goes back home and starts to play football until his

parents come back. He does his homework after supper. He usually has lots of weekend

homework, so he must do it for three hours . He usually goes to bed at about 11:00 p.m.

on Sundays. He often complains(抱怨) he has too much homework to do.

1.How often does Li Ping need to get up early?

A. Every day.                    

B. Five days a week.

C. Only at the weekend.            

D. Every day except on Sundays.

2.What does Li Ping do on Sunday mornings?

A. He goes to have lessons.          

B. He goes to a club.

C. He goes to the bookshop.        

D. He watches TV.

3.When does Li Ping do his weekend homework?

A. On Sunday evenings.            

B. On Sunday mornings.

C. On Saturday evenings.            

D. On Sunday afternoons.

4.Why does Li Ping have lunch in KFC on Sundays?

A. Because he's too busy.      

B. Because his parents aren't at home.

C. Because he gets up too late.  

D. Because his parents have lunch in KFC.

5.Which of these is not right?

A. Li Ping watches TV after supper on Saturdays.

B. Li Ping doesn't exercise on Sundays.

C. Li Ping watches too much TV On Saturdays and Sundays.

D. Li Ping goes to bed late on Saturday and Sunday evenings.

单项选择题