coulomb’s law?

Coulomb's law

Two charges q1 and q2 are 3m apart, q1 + q2 = 40 μC = a

(a) If one repels the other with F1 = 0.175 N, q1,q2 = ??

q2 = a - q1

F1 = k*q1*(a - q1) / r^2

0 = k*q1^2 - a*k*q1 + F1*r^2


q1 = {a*k + - √[(a*k)^2 - 4k*F1*r^2]} / 2k

= {40*10^-6 + - √[(40*9000)^2 - 4*9*10^9*0.175*9]}/2*9*10^9

= {35 μC; 5 μC}


q2 = a - q1

= {5 μC; 35 μC} ;;; Same Poarity





(b) If one attracts the other with a force of 0.225 N, what are the two

charges?

q1 = {a*k + - √[(a*k)^2 - 4k*F2*r^2]} / 2k

= {40*10^-6 + - √[(40*9000)^2 - 4*9*10^9*0.225*9]}/2*9*10^9

= {33.23 μC; 6.77 μC}


q2 = a - q1

= {6.77 μC; 33.23 μC} ;;; Opposite Poarity