Two tiny spheres of mass m = 9.80 mg carry charges of equal magnitude, 72.0 nC, but opposite sign. They are tied to the same ceiling hook by light strings of length 0.530 m. When a horizontal uniform electric field E that is directed to the left is turned on, the spheres hang at rest with the angle theta between the strings equal to 50.0

Question

anonymous · Answer

http://session.masteringphysics.com/problemAsset/1331112/7/21-82.jpg

anonymous · Answer

hello are you trying to solve for the force F here?

anonymous · Answer

no i need the magnitude of the field

anonymous · Answer

$$F_q=kq^2/r^2$$
$$r=2Lsin(\theta/2)$$
force in the y
$$Tcos(\theta/2)=mg$$
force in the x
$$F_E=F_q+mgtan(\theta/2)$$
$$E=F_E/q$$

anonymous · Answer

This is what I have so far, and when I solve for it I'm getting an incorrect answer

anonymous · Answer

F=kQ1Q2/d^2, where k=constant=6.25x10^-9 Coulomb
F=(6.25x10^-9)(72x10^-9)(72x10^9)/(.53)^2=1.15 x10^22 Newton

anonymous · Answer

for r I got .4479ish, .53 is L the length from the ball to the ceiling

anonymous · Answer

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