作者justalone101 (ㄚ挺)
看板Physics
标题[问题] 两题普物问题
时间Sun Mar 6 23:44:15 2011
跟电学有关
1. A cube of edge "a"(边长) carries a point charge q at each corner.
Show that the resultant electric force on any one of the charge
is given by:
F = 0.262q^2 / εa^2
2. Two positive charges +Q are held fixed a distance d apart. A particle
of negative charge -q and mass "m" is placed midway between them, then is
given a small displacement perpendicular to the line joinging them and
relased.
Show that
the particle describes SHM of period = (εmπ^3d^3/qQ)^1/2
第二题我算的答案是 ("2"εmπ^3d^3/qQ)^1/2
麻烦各位帮忙解题一下 谢谢!!
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1F：→ SmArTyau:第一题 从cube的最长的斜对角看 将它分成四层 03/07 02:10
2F：→ SmArTyau:分别为1 3 3 1颗电子 然後计算2 3 4层对第1层的力 03/07 02:11
3F：→ SmArTyau:第二题 F=-kx中的 k=4qQ/(πεd^3) T=2π[sqrt(m/k)] 03/07 02:15
4F：→ justalone101:抱歉~第一题我还是不太懂耶 还有第二题的k为什麽是 03/07 07:13
5F：→ justalone101: 4qQ/(πεd^3) 可以麻烦大大说明清楚一点吗? 谢谢 03/07 07:14
6F：→ ren1072:对角落的点电荷而言距离它a的电荷有三个//根号2*a的有三个 03/07 14:58
7F：→ ren1072:根号3*a的有一个... 03/07 14:59