How Does Coulomb's Law Determine Force in a Charged Square Configuration?

[v13tn1g]

Homework Statement

A square with side lengths 2.0 cm has a charge of -1.0x10^-6 at every corner. What is the magnitude and direction of electric force on each charge?

Homework Equations

Fe=kq1q2/r^2

The Attempt at a Solution

FeNet=kq1q2/r^2
=(9x10^9)(-1.0x10^-6)^2/(0.002)^2
=22.5 N

 

[Kurdt]

You will need to take into account the direction of the force. Set up some coordinate axes and treat the force from each of the 3 other charges on one charge as a vector. Once you've found one the others should be obvious.