1:1  03-08[物理]闫老师教你学会“双分析”
推荐理由：对于多状态问题要逐一状态进行受力分析和运动状态分析，即“双分析”。 讲解人：闫芳，北京市东城区优秀青年教师。善于指导学生学习方法，深受学生喜爱。 题面：教室装有磁性黑板，由于磁体之间有吸引力，所以内部装有磁铁的黑板擦可被吸在黑板上的任何位置而不会掉下来。若已知黑板擦的重力为1.5 N，黑板擦和黑板之间的吸引力恒为4 N不变。当对黑板擦施加方向竖直向下、大小为0.5 N的推力时，黑板擦恰能沿黑板表面匀速下滑。若要这个黑板擦沿黑板表面竖直向上匀速滑动，则需施加方向竖直向上的力，这个力的大小应为( ) A. 2 N B. 3.5 N C. 4.5 N D. 5.5 N 【答案及详解】 本部分内容设定了隐藏,需要回复后才能看到
同学们，你们学会“双分析”了吗？ |
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