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Goldenwind
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Homework Statement
http://session.masteringphysics.com/problemAsset/1001949/13/knight_Figure_25_69.jpg
An electric field 1.00×10^5 N/C causes the ball in the figure to hang at an angle. What is theta?
Homework Equations
E = F/q
F = mg
The Attempt at a Solution
The ball isn't accellerating, so it is in equilibrium. Sum of all forces is 0, so the tension force balences gravity + electric field.
E = F/q
F = Eq
F = 100000*(25*0.000001)
Fx = 2.5
F = mg
F = (0.002)(9.81)
Fy = 0.1962
Ft = Sqrt(Fx^2 + Fy^2)
Ft = 2.5076870697916038024546202698347
tan(theta) = Opp/Adj
tan(theta) = Fx/Fy
theta = arctan(2.5 / 0.1962)
theta = 85.5126 degrees
This answer is wrong.
Where is my mistake?
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