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Buffu
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Homework Statement
Two charges placed at circumference of a circle of radius ##a## at ##\pi/2## from each other. Find the relative magnitude of third charge kept on the circumference such that the system is at equilibrium.
Homework Equations
Coulombs law.
The Attempt at a Solution
Let ##Q## be the unknown charge and ##x## be the length of equal sides of the triangle . then I get,
$$F_{BA} = {-Qq \over x^2 } \left(\cos(135/2)\hat i + \hat j \sin(135/2) \right)$$
$$F_{CA} = {-q^2\over 4x^2(\cos (135/2))}(\hat i) $$Now the force on ##A## should be zero for the system to be in equilibrium but clearly there is a net force in -y direction that is not balanced by anything, so how the system is in equilibrium for any value of ##Q## ?
Where did I go wrong ?
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