六 05
![qiutopia](http://www.qiusir.com/wp-content/uploads/downloads/2018/03/fv.gif)
和往年相比,今年的高三串讲也推迟了一个月。返校第一周时间相对充足,把要看的书先放一边,趁着更新备考资料把一些繁杂的计算题目也大致过了一遍。关于高三复习,除完成夯实基础的底线,适当也和学生交流一点这个年段应试的上限题目,比如对这道有关“阻力与速度成正比”上抛运动的综合题就有了一个小的想法...
“均匀材料构成的导体圆环,略大于竖直放置的圆柱体。空间存在着垂直于柱体表面的辐射型磁场,圆环所处位置的磁感应强度B,圆环半径为R,质量为m,电阻r,竖直向上的初速度为
![v_0](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_8bcda5f030288c05bb245be5d42b3c07.gif)
![t_1](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_69ac49315fb75559bc7125a373ed5735.gif)
![t_2](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_76a9c0f8e913d97ec097e88ed8232da5.gif)
![q_1](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_28dc930e7c69157c9b0876863eee407c.gif)
![q_2](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_fa043c065dd111d926a3d140b618b05e.gif)
![Q_1](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_d47fb18b456b1f8392cb799b18529463.gif)
![Q_2](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_0f91906a35c86ed83e3f85281673751f.gif)
![v_\frac{h}{2}](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_0e39983abca7e2113cd4f0997e9531b3.gif)
![\frac{v_0}{2}](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_ff10b6240660dcca362be4b8cf6b322d.gif)
![\frac{\sqrt{2}}{2}v_0](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_e3a1506c984a8728cb7e1acdb4ca1fdd.gif)
具体考虑这个问题之前,想起之前借助WolframAlpha的帮助构造的一个受到和速度成正比阻力作用下的竖直上抛的模型[?]...
考虑到安培力是,上面题目对应受与速度成正比阻力的竖直上抛,那么就可以在之前构造的模型上重新考虑上面一些小问题。比如对
和
,先想到的是匀变速运动的中间时刻和中点的瞬时速度,同时进一步的量化是动量变化一半和动能变化一半的位置,然后分别从动量定理和动能定理考虑...
![qiutopia](http://www.qiusir.com/wp-content/gallery/physics/upupxiang.png)
如果仅研究上升过程中点前后的两部分,
![mgt_1+\int{kv}dt](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_e95df83adafcf49d4fec6089c019e6b5.gif)
![mgt_2+\int{kv}dt](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_ea17286932ff8f3f2412c95302edcf3d.gif)
![v_\frac{h}{2}>\frac{v_0}{2}](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_ba5d05f382d83a17e5b6785f270a624c.gif)
![mg\frac{h}{2}+W_{f1}](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_d6a8857e6042027c0988b68364229833.gif)
![mg\frac{h}{2}+W_{f2}](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_a385864cf1b94e1ae44678847f6fd521.gif)
![v_\frac{h}{2}< \frac{\sqrt{2}}{2}v_0](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_b5bfd6cbb625eaa6debba2acb2dced83.gif)
![-mgt-\int{kv}dt+\int{kv}dt=-mv_2-mv_1](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_b9c59efd78da849eb5725e99e0e2d94b.gif)
![v_\frac{h}{2}](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_0e39983abca7e2113cd4f0997e9531b3.gif)
![qiutopia](http://www.qiusir.com/wp-content/gallery/physics/yuquanqiang.jpg)
我能提出关于
![t_\frac{h}{2}](http://www.qiusir.com/wp-content/plugins/latex/cache/tex_15721b5cc010293fa2d463fedeb80111.gif)
P.S.有时间应该更新带电粒子在电容里运动的专题整理,特别是那个对称的偏移问题...