问题 选择题

宇航员在月球表面完成下面实验:在一固定的竖直光滑圆弧轨道内部的最低点,静止一质量为m的小球(可视为质点),如图所示,当给小球水平初速度V0时,刚好能使小球在竖直平面内做完整的圆周运动.已知圆弧轨道半径为r,月球的半径为R,万有引力常量为G.若在月球表面上发射一颗环月卫星,所需最小发射速度为

[ ]

A.

B.

C.

D.

答案

答案:A

阅读理解

Jack is an able(能干的)worker.He can do all the work in the factory and often helps his boss(老板),Mr. King.So his boss likes him and he gets much money.But he likes drinking and spends most money on drinks.When he drinks much,he can’t control(控制)himself.His wife(妻子)tells him to stop drinking,but he doesn’t listen to her.She has to leave him.Now he lives in a poor and old house alone(独自).

One Saturday evening,Jack feels very cold in his house.He can’t stay there and goes into a bar(酒吧).He drinks a lot,but he doesn’t have enough money with him.

Of course,he can’t pay for the drinks.The boss of the bar doesn’t let him out,so he begins to break the glasses and tables.A girl calls the police station and soon some policemen get there.They have to take Jack to the station.

“What do you bring me here for?”he shouts.

“We bring you here for drinking.”answers a policeman.

“That’s great!”Jack says happily.“Then when shall we start?”

小题1:Jack can get much money because _______.

A.he is the boss

B.he works in the factory for a long time

C.the boss likes him

D.he is able enough to help the boss小题2:Jack’s wife leaves him because _______.

A.he doesn't like her

B.he gets no money in the factory

C.he doesn’t stop drinking

D.he doesn’t do housework at home小题3:Jack is happy because he thinks_______.

A.the policeman will drink with him

B.the policeman pay for his drink

C.the policeman will make friends with him

D.the policeman wi1l give him some money

选择题