How many electrons should be removed from each of the two similar spheres each of 10g so that electrostatic repulsion be balanced by gravitational force.

Question

How many electrons should be removed from each of the two similar spheres each of  10g so that electrostatic repulsion be balanced by gravitational force.

anonymous · Answer

I think that you mean removing some electrons and adding the to the other ball!
It's obvious that the forces should be equal,(m1=m2=m, q1=q2=q)
F1=F2=>Gm1*m2/r^2  =  kq1*q2/r^2   => q^2=G*m^2/k
G=6.67300 × 10-11
k=9.109*10^9
m=.01kg
=>q=2.723*10^-12
q=ne=> n = 1.7018*$$10^{7}$$