Electric field at a point due to a subdivided object

AI Thread Summary
The discussion focuses on calculating the electric field at a specific point due to a uniformly charged strip of tape. The tape is divided into three sections to approximate each as a point charge. The user attempts to calculate the electric field from the second section but realizes their vector R calculation is incorrect. They provide their initial calculations and seek clarification on the error. The conversation highlights the importance of correctly determining the vector R for accurate electric field calculations.
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Homework Statement



http://imageshack.us/photo/my-images/403/haiss.jpg/
picture

A strip of invisible tape 0.12 m long by 0.014 m wide is charged uniformly with a total net charge of 3 nC (nano = 1e-9) and is suspended horizontally, so it lies along the x axis, with its center at the origin, as shown in the diagram.
Calculate the approximate electric field at location < 0, 0.03, 0 > m (location A) due to the strip of tape. Do this by dividing the strip into three equal sections, as shown in the diagram, and approximating each section as a point charge.
What is the approximate electric field at A due to piece #2?




Homework Equations



9e9*Charge*Vector Hat/(Vector Magnitude)^2

The Attempt at a Solution



okay so for tape #3 the Vector R is <0, 0.03, 0 > - <0.06, 0, 0> = <-.06, .03, 0>
That means magnitude is 0.0671
and that means Vector R Hat is <-.8942, .4471, 0>

plug this into 9e9*1e-9*<-0.8942, .4471, 0>/(0.0671)^2

and I get <1787.44, 893721, 0>

Which is wrong... why?
 
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before anyone wastes their time, my R vector was wrong
 
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