某个行星质量是地球质量的一半,半径也是地球的一半,则此行星上的重力加速度是地球上

题型:选择题

问题:

某个行星质量是地球质量的一半,半径也是地球的一半,则此行星上的重力加速度是地球上的(  )

A.0.25倍

B.0.5倍

C.4倍

D.2倍

考点:万有引力定律的其他应用
题型:选择题

Losing a job or not being able to find one almost always brings unwelcome changes. If you’ve lost a job, the first feeling is often one of shock. On top of the loss of income, many people find the whole routine of their life is shattered, their contact with other people reduced, their ambitions halted and their identity as a worker removed.
There may be good feelings too—it’s nice to be able to lie in bed in the morning, to spend more time with children, or to have more time to think—a better job may be just around the corner. But, unless a better job does turn up, chances are the days start getting longer and the time becomes harder to fill. Many people pass through periods of difficulty in sleeping and eating. They feel irritable and depressed, often isolated and lonely.
Despite all these problems, unemployment can be a chance for a fresh start. You can discover that it provides an opportunity to sort out or rethink what you want from life and how best you can get it. You can use the time to plan how to find a new job, learn a new skill, develop your hobbies, see if you can run your own business, do some voluntary work in your community or meet new people. It’s up to you.

According to the passage, continuing unemployment may cause ______.

A.absence of humot

B.lack of interest

C.waste of time

D.loss of appetite

题型:选择题
不定项选择
关于气体的压强,下列说法中正确的是(   )

A.温度升高,气体分子的平均速率增大,气体的压强一定增大

B.气体的压强等于器壁单位面积上、单位时间内所受气体分子冲量的大小

C.当某一密闭容器自由下落时,容器中气体的压强将变为零

D.气体的压强是由气体分子间的排斥作用产生的

题型:选择题

表现人物、动物身体及四肢关节比较柔和的运动过程,就不能呆板、机械地用直线中间画的方法来表现,而应当运用()运动技法,准确地表现它的中间变化过程。

A、弧形曲线

B、惯性

C、弹性

D、圆形

题型:选择题

原型定义的属性中,确保需求没有逻辑上的矛盾是下列哪种属性

A.一致性

B.完备性

C.可维护性

D.非冗余性

题型:选择题

在硅芯管穿越公路、铁路、沟渠、河流、街道时,尽可能采用非()施工方式。

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