The charges on two metallic balls are 5.0 and 7.0 coulombs respectively. they are kept 1.2 meters apart. what is the force of interaction between the two? (k = 9.0 * 10© newton·metersæ/coulombæ)

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?