More Math.

來源: 於 2011-09-17 07:14:05 [舊帖] [給我悄悄話] 本文已被閱讀：次

2)F(x)=k*intgdtfrom(-RtoR)Intg(2Pai*s*(t+x)/(s^2+(t+x)^2)^(3/2)ds from(0 to squat(r^2-t^2)=k(20/3)Pai*x. k(20/3)Pai(R)=mg, SO,m*dx^2(x)/d^2(t)=-F(x)=-mg/R,...,the same as 1).