# What is the electric field strength at the center of the triangle?

## Homework Statement

What is the electric field strength at the center of the triangle?

Three 13.0 -cm-long rods form an equilateral triangle. Two of the rods are charged to + 19.0 nC, the third to - 19.0 nC .

What is the electric field strength at the center of the triangle?

## Homework Equations

E=(kq)/r^2 lambda=deltaQ/deltax

## The Attempt at a Solution

I've attempted this problem about 4 times and got all different but wrong answers. In each attempt I figured that the electric fields created by the two positively charged rods cancel each other out everywhere (This is where I believe I have made my mistake) and that the electric field depends only on the negative charged rod. I also figured by symmetry that the components of the electric field to the left and right (x-axis I chose) cancel each other out and the only electric field felt at the center is downwards (Y-axis I chose).

Is my mistake based on that I figured the two positively charged rods cancel each others electric fields out? I'm looking for some tips and hints to get me on track for this problem.

Thank you.

Related Introductory Physics Homework Help News on Phys.org
Hootenanny
Staff Emeritus
Gold Member
Okay, lets start with the expression for the electric field of a finite line of charge.

is it E line=(K)(2)absolutevalue(lambda)/r ?

=(k)(2)absval(Q/x)/r

Hootenanny
Staff Emeritus