*sigh*, Another long semester of physics...(adsbygoogle = window.adsbygoogle || []).push({});

Anyways, here we go ! Here's the problem:

Calculate the magnitude of the electric field at the center of a square with sides 27.3 cm long if the corners, taken in rotation, have charges of 1.10 microC, 2.20 microC, 3.30 microC, and 4.40 microC (all positive).

Using Pythagorean's thereom I find the radius to all these Point Charges to be 0.193040 m

So then I try plugging All this info in the Eq'n for finding Electric field magnitude and direction.. E = kQ/(r^2) where k = 9.0*10^9

At first, I tried E = (k/r^2)(Q1 + Q2 + Q3 + Q4)

and got 2660000. Which, apparently, is wrong.

From looking at the study guide and the book, I'm guessin I'm leaving out some very important trigonometric calculations necessary to go further.. So I decided to calculate the electric field produced by each point charge at the center

E1 = 265668

E2 = 531337

E3 = 797005

E4 = 1062674

Then I Broke Each into their Components by arbitrarily assigning them corners of a square

E1x = 187855

E1y = -187855

E2x = -375712

E2y = -375712

E3x = -563568

E3y = 563568

E4x = -751424

E4y = 751424

Then I Added up the components, and got -1 for the sum of x, 751424 for the sum of y. I then applied the pythagorean theorem and rejoiced in excitement as I got the wrong answer.. again.. after all that. Can someone help me out here ? ?

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# Homework Help: Electric Field at the Center of a Square of Point Charges

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