# 4 identical point charges on a rectangle's corners

1. Oct 16, 2009

### S.U.S

hi ,, I'm having this problem that i tried to solve but I couldn't so if any one could help with EXPLANATION I would be greatful

1. The problem statement, all variables and given/known data

Four identical point charges (q = +10.0 µC) are located on the corners of a rectangle. The dimensions of the rectangle are L = 60.0 cm and W = 15.0 cm. Calculate the magnitude and direction of the net electric force exerted on the charge at the lower left corner by the other three charges.

2. Relevant equations

coulomb's law

3. The attempt at a solution

I couldn't really

P.S : I'm not an english native speaker so if there is any thing wrong above please forgive me

thanks

2. Oct 16, 2009

### rl.bhat

Hi S.U.S. welcome to PF.
If A B C and D are the corners of the rectangle, then using coulomb's law, find the force on D by A, B and C. Forces due to A and C are perpendicular to each other. Resolve force on D due to B into two component. One along AD and another along CD. Find the net forces along these two directions and then find the resultant force.

3. Oct 16, 2009

### arithmetix

yes, the vector sum of the 3 forces is what you want.
(Perhaps you will be surprised to see how large that resultant force is!)

4. Oct 16, 2009

### S.U.S

thanks ,, I'll try and tell you what happens