质量为m的物体静止在粗糙的水平面上,当此物体受水平力F作用运动距离S时,动能为E

题型:选择题

问题:

质量为m的物体静止在粗糙的水平面上,当此物体受水平力F作用运动距离S时,动能为Ek1,而当此物体受水平力2F作用相同的距离时,其动能为Ek2,则(  )

A.Ek2=Ek1

B.Ek2=2Ek1

C.Ek2>2Ek1

D.Ek1<Ek2<2Ek1

考点:动能定理
题型:选择题

卫生服务市场的失灵表现在那些方面?

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由于证券自营活动有利于活跃证券市场、维护交易的连续性,因此许多国家都给以特殊的自由宽松政策,予以支持。 ( )

题型:选择题

印染、纺织等工业用水中铁的含量必须在()mg/L以下。

A.0.05

B.0.1

C.0.5

D.0.8

题型:选择题

输送机启动顺序为,输送机一-破碎机一-转载机。

题型:选择题

One of the most important things in the world is friendship. In order to have friends, you have to be a friend. But how can you be a good friend at school?

Listen—Listen when they are talking. Don’t say anything unless they ask you a question. Sometimes it’s not necessary for you to have anything to say; they just need someone to talk to about their feelings.

Help them—If your friend is ever in need of something, be there to help them. You should try to put them first, but make sure you don’t do everything they want you to do. Try to take an extra pencil or pen with you to classes in case they forget one. Have a little extra money in your pocket in case they forget something they need.

Be there for them—Be there for your friends to help make them feel better in hard times. Marilyn Monroe, a famous U.S. actor, once said, “I often make mistakes. Sometimes I am out of control, but if you can’t stay with me at my worst, you are sure not to deserve to be with me at my best.” Always remember this! If you don’t want to stay with your friends when they’re in hard times, then you don’t deserve to be with them when they’re having a good time!

_________—Try to make plans with your friends. Go shopping, go for ice cream, have a party, go to a movie and so on. Take time to know each other even better by doing something you both enjoy. By planning things together, you both can have a good time. And you’ll remember these things when you’re all old!

小题1: While your friend is talking to you about his or her feelings, you should______________.

A.give him or her some advice

B.just listen unless asked

C.calm him or her down

D.share your feelings as well小题2:When we provide help for our friends, we should ___________.

A.try to do everything for them

B.put them before ourselves

C.change their bad habits first

D.ignore their faults小题3:What can we learn from Marilyn Monroe’s words?

A.Life without a friend is death.

B.A friend is easier lost than found.

C.A friend in need is a friend indeed.

D.A man is known by his friends.小题4: Which of the following can be put in the blank of the last paragraph?

A.Make plans

B.Enjoy yourself

C.Understand your friends

D.Play with your friends小题5:The passage is mainly about _______.

A.how to find a good friend

B.how to help friends in trouble

C.How to be a good friend

D.how to make more friends

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