A plastic rod 1.9 m long is rubbed all over with wool

[TehFabled]

Homework Statement

A plastic rod 1.9 m long is rubbed all over with wool, and acquires a charge of -6e-08 coulombs. We choose the center of the rod to be the origin of our coordinate system, with the x-axis extending to the right, the y-axis extending up, and the z-axis out of the page. In order to calculate the electric field at location A = < 0.7, 0, 0 > m, we divide the rod into 8 pieces, and approximate each piece as a point charge located at the center of the piece.

Homework Equations

Pythagorean theorem

The Attempt at a Solution

A) Found the length of a single section of the rod to be .2375
B) length from the center to the center of section 2 to be <0,.594,0>
C) Charge on piece number 2 to be 7.5e-9
D) Approximating piece 2 as a point charge, what is the electric field at location A due only to piece 2?

This is where I got stuck
Found the unit vector to be (.762, .647, 0)
I plugged in my values to the point charge formula multiplied by the unit vector and got <-61.03,-51.823,0>
I don't know where I've gone wrong. Tried redoing the same steps in another version of the problem, and can't get the solution

 

[ehild]

Homework Statement

A plastic rod 1.9 m long is rubbed all over with wool, and acquires a charge of -6e-08 coulombs. We choose the center of the rod to be the origin of our coordinate system, with the x-axis extending to the right, the y-axis extending up, and the z-axis out of the page. In order to calculate the electric field at location A = < 0.7, 0, 0 > m, we divide the rod into 8 pieces, and approximate each piece as a point charge located at the center of the piece.

Homework Equations

Pythagorean theorem

The Attempt at a Solution

A) Found the length of a single section of the rod to be .2375
B) length from the center to the center of section 2 to be <0,.594,0>
C) Charge on piece number 2 to be 7.5e-9
D) Approximating piece 2 as a point charge, what is the electric field at location A due only to piece 2?

This is where I got stuck
Found the unit vector to be (.762, .647, 0)

Check the sign of the components.

I plugged in my values to the point charge formula multiplied by the unit vector and got <-61.03,-51.823,0>
I don't know where I've gone wrong. Tried redoing the same steps in another version of the problem, and can't get the solution

You have a sign error. And also some minor rounding errors.