Two charged balls which are near each other will exert a force on each other: attractive if they are oppositely charged, and repulsive if they are similarly charged. The magnitude of the force is given by
where F is in N, k is a constant 9 x 109 N m2/C2, q1 and q2 are the charges on the balls measured in C, and r is the distance between the balls in m.
In a hypothetical situation, two balls of positive charge exert a force 12 N on each other. The charge on ball A is 2 C. If the charge on ball A is increased to 8 C, and all else unchanged, what would the force be?