1. The problem statement, all variables and given/known data Hi, I am stuck with this homework. I have been asked to make an equation out of a diagram for V(z) using V=kQ/r equation, where z is a positive axis centred with four negative charges. Here is the diagram. 2. Relevant equation E=F/q F of point charge: F=kQq/r^2 E=kQ/r^2 V=kQq/r ~U=V*q & KE=0.5m*velocity^2 r=distant of the point from the point charge q k=1/4*pi*[E][/0] 3. The attempt at a solution I have already completed the (a) and (b) parts. However, for part (b) I could only make V(z)=Q/(4*pi*Enod)*r where r = 0.5*sqrt([d^2+(2Z-d)^2]) from the r12. I found r by taking all point charges distant together by saying r12 of the first 2 charges are equal and r34 of the 3rd and 4th is same. Therefore, Vtotal=KQ*[(2/r12)+(2/r34)]. But how do I make it as V(z)=-Q/pi*Enod.... because currently I am getting V(z)=-Q/8*pi*Enod(sqrt([d^2+(2Z-d)^2])). Am I doing something wrong. Thanks for any insight or solution for the other parts would be very helpful. And how do I do Q 1. (c),(d)& (f)??