Two identical objects have charges from +6.0*10^-6 and -2.0*10^-6, respectively. When placed a distance d apart, their force of attraction is 2,0N. If the objects are touched together, then they moved to a distance of separation of 2d, what will be the new force between them?

Ans: I tried the finding the distance d and then finding the new force, but i am not getting the value, i even tried the inverse square law , i got the same answer but not the one required 0.17N.

2 answers

If you touch them, the charge neutralizes, and divides, the new charge on each is 2E-6, so the product is 4E-12, as compared to the original 12E-12
or 1/3 the force due to charge.

distance doubling, makes the force 1/4

new force= 1/3*1/4 old force., or you can work it out new force
0.81