Electrostatics not on the same axis

[Jabababa]

Homework Statement

https://docs.google.com/viewer?pid=...0846ea2fbce00fd8bb0b&a=bi&pagenumber=14&w=791

#39.

Homework Equations

Ep=KQ1Q2/R

The Attempt at a Solution

I don't know how to solve this because its not on the same axis.Please someone enlighten me on how to do it at different angle!

 

[ap123]

The link doesn't work :(

 

[Jabababa]

try now i think i attached the picture on it!

 

[ap123]

Do you know the relation between work and electric potential energy?

 

[Jabababa]

Work = the change in electric potential energy? Is that what you are referring to?

 

[ap123]

Work = the change in electric potential energy? Is that what you are referring to?

Yes.
Can you work out the potential energy for the 2 configurations?

 

[Jabababa]

yes I have

kq1q2/0.6^2 Epi
kq1q2/0.4^2 Epf

then what should I do

 

[ap123]

yes I have

kq1q2/0.6^2 Epi
kq1q2/0.4^2 Epf

then what should I do

This is the electric force, not the potential energy.
The PE varies as 1/r, not 1/r²

Also, there are 2 fixed charges - you've only accounted for 1 of them.