Electrostatic equilibrium, deflection of a cobweb

  • #1

Homework Statement



9KbiO40.png

Homework Equations



After creating a FBD and analyzing the forces, I get the equation for the angle as

## tan \theta = \frac{k q^2}{m g r^2} ##

The Attempt at a Solution


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I have tried to find a way to find the distance between the charges ## r ##, but the only way I can think of to find it required the angle. I do not know how the question can be solved without knowing at least one of the two variables, and my first inclination is just to assume there is not enough information.

Any help would be appreciated! Thanks!
 

Answers and Replies

  • #2
CWatters
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I think you can write another equation for r in terms of theta using the geometry alone..

Hint: You are given the dimension 0.35m
 
  • #3
Doc Al
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I have tried to find a way to find the distance between the charges r r , but the only way I can think of to find it required the angle.
Find the relationship between r and ##\theta##.

(CWatters beat me to it while I was snoozing!)
 

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