Answer to Question #135232 in Physics for jason

Question

Two metal spheres, both with mass 50 kg, are suspended from thin metal wires at a distance of 3 m between their centers and begin to attract each other gravitationally. An engineer wishes to put equal amounts of charge on each sphere until the resulting electrostatic repulsion exactly balances the gravitational attraction. How much charge should be placed on each sphere in order to accomplish this? Show all calculations (attaching a Google Doc, photo, or other documentation as necessary)

Answer 1

$$\frac{Gm^2}{r^2}=\frac{kq^2}{r^2}$$

$$q=m\sqrt{\frac{G}{k}}=50\sqrt{\frac{6.67\cdot10^{-11}}{8.99\cdot10^{9}}}=4.3\cdot10^{-9}C$$