Electrostatic Equilibrium Problem

[ommmmm]

Electrostatics Equilibrium Problem-It is required to hold four equal point charges +q each in equilibrium at the corners of a square. Find the point charge that will do this if kept at the center of the square?
I am doing the basics of coulomb's law,can anyone explain this to me?
I cannot do this problem,the problem seems to be complex to me?

 

[Doc Al]

Start by drawing a diagram. Pick one of the charges. Figure out what force the other three charges exert on it. (The forces are vectors, so be careful.)

Once you do that you'll be in a better place to figure out what that central charge must be.

 

[ommmmm]

Sir,what to do about the direction of the vector?

 

[Doc Al]

Sir,what to do about the direction of the vector?

Start by drawing that diagram.