What is the magnitude E of the field?

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Homework Statement




Two tiny spheres of mass = 7.20 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 between the strings equal to 50.0 degrees.

What is the magnitude E of the field?


Homework Equations


Fe1 = Eq
Fe2 = (Kq1q2)/r2
Fg = mg



The Attempt at a Solution



I assumed that the state it is in is in equilibrium so I set up:

ƩF = Fg + Fe1 + Fe2 + T = 0

ƩTx = Tcosθ - Fe1 + Fe2 = 0

θ being 65 degrees since I split the triangle made by the 50 degrees into 2 right triangles.

ƩTy = Tsinθ - mg = 0

T = (Fe1 - Fe2)/cosθ

Ty = (Fe1 - Fe2)tanθ - mg = 0

Fe1 = mg/tanθ + Fe2

E = (mg/tanθ + kq1q2/r2)/q

(I found r to be .448 using the right triangles I formed)

I plugged in all the given values and I've got...1.17 x 10^6

Which is wrong. Can someone please explain what I messed up on?
 
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Whoops I used the wrong angle during my calculations so my actual answer is 4.6 x 10^5 but it is still wrong
 
To solve this, I first used the units to work out that a= m* a/m, i.e. t=z/λ. This would allow you to determine the time duration within an interval section by section and then add this to the previous ones to obtain the age of the respective layer. However, this would require a constant thickness per year for each interval. However, since this is most likely not the case, my next consideration was that the age must be the integral of a 1/λ(z) function, which I cannot model.
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