Hello all. I am in my second week of physics and have come across a problem I can't figure out for the life of me. I'm pretty sure i'm using the wrong formula to figure it out. Heres the question: Two charges, Q1 and Q2, are separated by 4·cm. The repulsive force between them is 64·N. In each case below, find the force between them if the original situation is changed as described. a. The magnitude of charge Q1 is reduced by 1/2. b. The distance between the charges is doubled? c. The magnitude of charge Q2 is increased by 16 and the distance between the charges is increased to 8·cm. Now I have been assuming that each charge is 32 N. I am using the formula kQ1Q2/r2. When I do (9x10^9)(16)(32)/16 I come up with 2.88e11 which can't possibly be the correct answer. Can someone point me in the correct direction to solve this problem? Thank you.