Problem Three
[tex]\dfrac{F_{2}}{F_{1}} = \dfrac{\dfrac{k*3q_1*3q_2}{r^2}}{\dfrac{k*q_1*q_2}{r^2}}[/tex]
The ks, rs, q1, q2 all cancel out.
You are left with F2/F1 = 9/1
The answer is C
Problem Four
This problem is a bit harder. In the first place one of the charges must be - otherwise the force will not be an attractive one which is what the question implies. So let q < 0.
That aside, I don't know how the acceleration could be a constant. As the distance decreases the force increases and therefore so does the acceleration. But it is is not a constant.
I would say that the answer is B.
