Question

Three charges are arranged as shown in the figure below. Find the magnitude and direction of the electrostatic force on the charge q = 5.12 nC at the origin. (Let r₁₂=0.280 m.) 

 magnitude _______ 

 direction _______ 

Answer 1

force due to 6 nC

F1 = k q1 q2 /r^2

F1 = 9*10^9* 5.12*6*10^-18 / ( 0.28^2)

F1 = 3.527*10^-6 N

force due to - 3nC

F2 = 9*10^9* 3*5.12*10^-18 / ( 0.1^2)

F2 = 13.824*10^-6 N

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a)

net force acting on q

F^2 = F1^2 + F2^2

F = 14.27*10^-6 N

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b)

Direction,

x = 180 + arctan ( F2 / F1)

x = 255.687 ccw from +x axis

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