Answer to Question #230246 in Physics for Soriano

Question

How large should the charge of each sphere be so that the repulsive electric force between the attractive gravitay force between them. Mass of sphere= 8kg

Answer 1

$$k\frac{q^2}{r^2}=G\frac{m^2}{r^2}\\q=m\sqrt{\frac{G}{k}} \\q=8\sqrt{\frac{6.67\cdot10^{-11}}{8.99\cdot10^{9}}}=6.89\cdot10^{-10}\ C$$