(Solved): (5\%) Problem 12: Two polystyrene balls have the same charge. Each ball has an excess of \( N=10^{2 ...

(5\%) Problem 12: Two polystyrene balls have the same charge. Each ball has an excess of \( N=10^{20} \) protons. The balls are initially separated by a distance, \( d \) \( =I .1 \mathrm{~m} \). The Coulomb constant is \( k=8.988 \times 10^{9} \mathrm{~N} \mathrm{~m}^{2} / \mathrm{C}^{2} \). A \( 50 \% \) Part (a) Write an expression for the charge on one of the balls, \( Q \), in terms of the charge on a proton \( e \) and the number of excess protons \( N \), D. A. \( 50 \% \) Part (b) What is the magnitude of the force between the balls, \( F \), in newtons?