Electric field and an equilateral triangle

[abeltyukov]

Homework Statement

Three 8 cm long rods form an equilateral triangle. Two of the rods are charged to +8 nC, the third to -8 nC. What is the electric field strength at the center of the triangle?

Homework Equations

E = 4piKλL

The Attempt at a Solution

I found the radius of the triangle to be 4.2688 cm. I tried doing E = 4(pi)(9 x 10^9)(100 nC/m) (.042688 m) but that seems wrong. Is L not the radius of the triangle?


Thanks!

 

[turdferguson]

Whats the height of the triangle? Divide that by 2

 

[abeltyukov]

I still don't get the right answer when I plug in 0.0472 m for L. Any ideas?

Thanks!

 

[turdferguson]

Thats still not it...start by finding the height

 

[abeltyukov]

The height is 4.72 cm, right? sqrt (8^2 + 4^2). Where do I go from there?

Thanks!

 

[turdferguson]

This is not resolving vectors if that's what youre thinking. The hypotenuse is 8 cm and one of the sides is 4 cm. Then you need to cut that height in half