如h所示,一表面光滑、与水平方向成60°角他绝缘直杆AB放在水平方向他匀强电场中

题型:问答题

问题:

如h所示,一表面光滑、与水平方向成60°角他绝缘直杆AB放在水平方向他匀强电场中,其下端(B端)距地面高度h=0.8m.有一质量为m=500g他带电小环套在直杆上,正以某一速度沿杆匀速下滑,小环离杆后正好通过B端他正下方P点处.求:

(1)小环离开直杆后运动他加速度四小和方向;

(2)小环在直杆上匀速运动速度他四小v0

考点:带电粒子在电场中运动的综合应用
题型:问答题

子宫肌瘤合并妊娠的治疗原则是()

A.采用保守治疗

B.妊娠4个月时行肌瘤切除

C.药物流产终止妊娠

D.剖宫取胎同时切除肌瘤

E.行宫颈环扎防止流产、早产

题型:问答题

世界人口受到的人工辐射源的照射中,居于首位的是()。

A、大气层核实验

B、医疗照射

C、地下核试验

D、核能生产

题型:问答题

Questions 53 to 57 are based on the following passage:(10分)To the people of ancient Egypt,life on earth was short.Life after death,however,was eternal. Therefore they built their tombs of stone and they took their possessions with them into another world. The more important the people,the greater the tomb.The Pharaohs were the rulers of the country and when they died they became gods.Many of their tombs remain,and some have become a wonder of the world.These are the pyramids.The purpose of these stone mountains was to protect the burial chamber form the weather and from thieves who might try to steal the gold,jewels and precious possessions placed there to accompany the dead ruler into eternal life.Their shape,with four triangular sides spreading from a single point,represented the rays of the sun.their position on the west bank of the River Nile was where the sun set every day and where they believed it began its journey into the other world.All the burial grounds in ancient Egypt were on the west bank of the river.

Whose Tombs were the largest and the most impressive of all

A.The tribe leaders’tombs.

B.The Pharaohs’tombs.

C.The tombs of those who built them.

D.The rulers’wives.

题型:问答题

棉制货物包装袋

题型:问答题

下列法律概念中,属于关系概念的有( )。

A.原告

B.赔偿责任

C.所有权

D.违约

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