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WeiLoong
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Homework Statement
IF the resultant electric field at D due to the three point charges is zero, find the magnitudes of q1 q2 in terms of q
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Homework Equations
Electric Field
The Attempt at a Solution
Ex = E(q1) + E(q2)x = k q1 / AB^2 + k q2 cosθ / BD^2
Ey = E(q2)y + E(q) = k q2 sinθ / BD^2 + k q / CD^2
must be
k q2 cosθ / BD^2 = - k q1 / AB^2
k q2 sinθ / BD^2 = - k q / CD^2
then
q1 = q AB^2 / (tanθ CD^2)
AB = CD
tanθ = AB / BC
then
q1 = q BC / AB = 2 q
and
q2 = - q1 BD^2 / (cosθ AB^2)
cosθ= BC / BD
then
q2 = - q1 BD^3 / (BC AB^2) = - q (BD / AB)^3 = -11,2 q
Did i make some mistake here?