问题 选择题

据国外媒体报道,2010年1月12日,美国宇航局最新天文望远镜-广域红外探测器“WISE”发现一颗围绕太阳运行的小行星,代号为“2010AB78”,“WISE”观测的数据显示,该小行星与太阳的距离约等于地球与太阳的距离,但由于其轨道倾斜,所以离地球很远,不会对地球构成任何威胁.已知火星围绕太阳公转的周期约为2年,假定该小行星和火星均以太阳为中心做匀速圆周运动,则小行星和火星绕太阳运行的速度的比值约为(  )

A.

1
2

B.

2

C.

3
1
2

D.

32

答案

万有引力等于向心力

G

Mm
r2地
=m
4π2
T2地
r

G

Mm
r2火
=m
4π2
T2火
r

G

Mm
r2小
=m
4π2
T2小
r

根据题意

T:T=2:1

由以上三式解得

r:r=

34
:1

T=1年

由v=

2πr
T
,得到

v:v=

32
:1

故选D.

阅读理解

阅读理解。

                                          The Painting

        A new painting was hanging in the Hemlock Mills Art Gallery. Throughout the day, visitors stood before the new exhibit(展品) and watched to guess what it meant.

        "I think it's a terrifying monster," said a man. "There's no name on it, but I'm sure is was drawn by a famous artist. "

        "I would say that it's a picture of a park as seen from an airplane, "

another man said. "I see many trees and roads. "

        Miss Culture, the local art reporter who worked for "The Hemlock

Weekly News" , said proudly, "This is clearly a masterpiece(杰作) created by an artist who wishes to be not to known to other people. The beautiful lines

of color show a person who is looking back at an exciting lifetime of

success!"

        At that moment, Mr. Lightman, the gallery curator (馆长) , came into the room. "Isn't it great?"he asked with a big smile on his face."My three-year-old son did that this morning. He says it's a maze(迷宫) . I think it's

amazing ! "                                                                   

1. The reason visitors are busy talking about the painting is         .

A. it was painted really beautifully

B. they didn't know what it meant

C. it was painted by a famous artist

D. it was a masterpiece in that time

2. Miss Culture enjoyed the painting a lot _         .

A. because it was from a great artist

B. though it was painted badly

C. because other people didn't understand it

D. but she herself didn't understand it

3. What does"He says it's a maze. I think it's amazing ! "really mean?

A. It's a great painting.

B. It's only a joke.

C. It's just for fun.

D. It's a masterpiece from an artist

问答题 简答题