Let's visualize the problem in the figure below:
From this figure, let's consider the force on a positive charge in the vertical direction.
The forces balance at equilibrium.
Two tiny spheres of mass m = 3.00 mg carry charges of equal magnitude, 72.0nC, but opposite sign. They are tied to the same ceiling hook by light strings of length 0.530m. When a horizontal uniform electric field E that is directed to the left is turned on, the spheres hang at rest with the angle θ between the strings equal to 50.0 degrees in the figure below.
What's the magnitude E of the field and which ball (left or right) has a positive charge?
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What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Electric Field concept. You can view video lessons to learn Electric Field. Or if you need more Electric Field practice, you can also practice Electric Field practice problems.