如图所示,弹簧振子在振动过程中,振子从a到b历时0.2s,振子经a、b两点时速度

题型:选择题

问题:

如图所示,弹簧振子在振动过程中,振子从a到b历时0.2s,振子经a、b两点时速度相同,若它从b再回到a的最短时间为0.4s,则该振子的振动频率为(  )

A.1Hz

B.1.25Hz

C.2Hz

D.2.5Hz

考点:简谐运动的振幅简谐运动的周期、频率和角频率
题型:选择题

A voyaging ship was wrecked during a storm at sea and only two of the men aboard were able to swim to a small, desert-like island. Not knowing what else to do, the two survivors agreed that they had no alternativethan to pray to God.

However, to find out whose prayers were more powerful, they agreed to divide the territory between them and stay on opposite sides of the island.

The first thing they prayed for was food. The next morning, the first man saw a fruit-bearing tree on his side of the island, and he was able to eat its fruit. But the other man’s parcel of land remained barren.

After a week, the first man became lonely and decided to pray for a wife. The next day, another ship was wrecked and the only survivor was a woman who swam to his side of the island. But on the other side of the island, there was nothing.

Soon thereafter the first man prayed for a house, clothes and more food. The next day, like magic, all of these things were given to him. However, the second man still had nothing.

Finally, the first man prayed for a ship so that he and his wife could leave the island, and in the morning he found a ship docked at his side of the island.

The first man boarded the ship with his wife and decided to leave the second man on the island, considering the other man unworthy to receive God’s blessings since none of his prayers had been answered.

As the ship was about to leave, the first man heard a voice from Heaven booming, “Why are you leaving your companion on the island?”

“My blessings are mine alone since I was the one who prayed for them,” the first man answered. “His prayers were all unanswered and so he doesn’t deserve anything.”

“You are mistaken!” the voice rebuked him. “He had only one prayer, which I answered. If not for that, you would not have received any of my blessings.”

“Tell me,” the first man asked the voice, “what did he pray for that I should owe him anything?”

“He prayed that all your prayers would be answered.”

For all we know, our blessings are not the fruits of our prayers alone, but those of another praying for us. So what you do for others is more important than what you do for yourself.

小题1:The first man’s wife is _____.

A.a swimmer who got to the island by accident

B.an angel sent by God to keep him company

C.a survivor from another wrecked ship

D.a native person on the desert-like island小题2:The underlined word “barren” in Paragraph 3 is closest in meaning to _____.

A.isolated

B.unproductive

C.fertile

D.dry小题3:Which of the following is true about the second man?

A.He didn’t deserve any blessing from God.

B.None of his prayers was answered by God.

C.He is not brave enough to tell God his needs.

D.His prayer helped his companion get out of trouble.小题4:What’s the moral of the story?

A.Never judge a person by appearance.

B.Don’t lose heart in trouble.

C.Helping others is helping ourselves.

D.Greed is the root of all evil.

题型:选择题

在泥泞路段遇驱动车轮空转打滑时如何处置

A.在从动轮下铺垫砂石

B.换高速挡加速猛冲

C.在驱动轮下铺垫砂石

D.猛打转向盘配合急加速

题型:选择题

压疮的康复治疗中,“有一定杀菌作用”属于()

A.光疗

B.超短波

C.漩涡浴

D.湿一半湿雷呋奴尔敷料

E.湿一半湿生理盐水敷料

题型:选择题

生产管理系统实用化评价验收分为各单位实用化自评价、远程数据检查和()

A.远程数据复查

B.现场评价验收

C.现场实用化验收

题型:选择题

聚丙烯装置挤压造粒系统挤压机模板加热的方式可采用()。

A、电加热

B、低压蒸气

C、高压蒸汽或热油

D、中压蒸气

更多题库