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mdxod
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Homework Statement
http://classes.uleth.ca/200503/phys2000a/private/ass02sol_files/image002.gif
With [tex]\theta[/tex] = 27 degrees, d = .015m, q2 = 6.4 *10^-19, q3 = q4 = -4.8 *10^-19.
Problem states: Find the distance D between the origin and particle 2 if the net force on 1 due to the others is 0.
Homework Equations
F = Kq1q2/ d^2
finding hypot. of a triangle
The Attempt at a Solution
So pretty much...there are no forces in the y direction due to the fact that F13y cancels out F14y. I'm getting really mixed up with the numbers and am not getting to the correct answer. but anyways i will show you what i have done.
(1) F13 + F14 can be = 2* F13 (you can pick F14...it doesn't really matter i just did F13)
so F13 = Kq1q3/ r^2, where r is the dashed lines.
For F12, its = Kq1q2 / (d+D)^2
so Fnet = 0 = 2*F13 + F12
(2) So next, i went to find "r" which is the dashed lines or the distance between q1 and q3...found r = d/(cos 27)
(3) Next is the actual set up..so i have: {2*F13 + F12}
[2Kq1q3] / [(d/cos27)^2] *cos 27 + [Kq1q2] / [d+D]^2 = 0
I know that K and q1 will cancel out.
[q2] / [d+D]^2 = [2q3*cos27] / [d/cos27]^2
from here...when i try to plug in and solve for D...i keep getting negative answers
or ones that just arent correct... but anyways if i were to go further with this problem to just solve for D without any calculations...i would have.
[d+D]^2 = [d*q2] / [2*q3*(cos 27)^3]
then square root both sides...and subtract "d"...
but after doign this and all the calculations, its still not working out to a correct answer. Thanks for any help.
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