Jawabanmu

2014-08-16T08:28:20+07:00
F = k . q . q / r^2
F= 9×10^9 Nm^2/C^2 × 50C × 90C /( 0,3m)^2
F=40500x10^9 Nm^2/0,09m^2
F=4500×10^7 N