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( 2012年2月浙江六校联考)如图所示,质量为m、电荷量为e的质子以某一初动能Ek从坐标原点O沿x轴正方向进入场区,若场区仅存在平行于y轴向上的匀强电场时,质子通过P(d ,d)点时的动能为5Ek;若场区仅存在垂直于xoy平面的匀强磁场时,质子也能通过P点。不计质子的重力。设上述匀强电场的电场强度大小为E、匀强磁场的磁感应强度大小为B,则下列说法中正确的是

A:

B:

C:

D:

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D

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    My heroes are the Singapore Women's Everest Team.In 2009,they became the first all-women team to climb Mount Everest.The team of six young women trained for seven years before they climbed the mountain.It was difficult for them to train because Singapore doesn't have any snow or any mountains.But they didn't stop,and in the end they made it.They Worked hard every day for their dream so I really admire them.

——Lance Reed, 16, from Britain

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——Mark Sterling,l7,from America

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——Richard Hale, 18,from Australia

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