Electric Field at Point Z, Two Charges

AI Thread Summary
The discussion revolves around calculating the electric field force at point Z due to two charges. The initial calculations were incorrect due to a failure to square root the radius and confusion between sine and cosine functions for the components. After several attempts, the participant adjusted their approach and realized they had omitted a sine factor in their calculations. Ultimately, they clarified that sin(180-theta) equals sin(theta), which helped refine their answer. The correct electric field force was determined to be approximately 1.21*10^5.
mike_302
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Homework Statement



I have drawn the diagram on the attached page... IT contains all information. The question is simply to determine the electric field force at point Z (which is at the very upper edge of the page)



Homework Equations



epsilon= Fe/q


The Attempt at a Solution



scan0001.jpg


I just noticed I forgot to square root the radius (rAZ and rBZ) in the top right corner.. that changes my answer, but not to the right answer... Now I get 1.44*10^5 . Correct answer is 1.21*10^5

What's wrong :S
 
Last edited:
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I think it should be sin(90 - theta), not sin(theta)
 
woah... woah... why? tan(theta)=.04/.03 ... that's unarguable... that gives my radius...

And in the Y-component part, we are taught to use sin(theta) for Y-components, where theta is the angle from the positive x-axis.
 
Sorry, I confused sin with cos :S

Edit2: I keep getting 1.15 * 10^5
 
Last edited:
Figured it out... I dropped the sin(53.13) when I multiplied by 2... but to answer your question, sin(180-theta)=sin(theta)
 

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