Solve Point Charge Deflection: Potential Difference Between Plates

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Homework Help Overview

The problem involves a point charge suspended between the plates of a parallel-plate capacitor, where the charge experiences a deflection due to the electric field created by the potential difference between the plates. The mass of the charge and its angle of deflection are provided, along with the separation between the plates.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationship between potential energy and the charge's position, questioning how to determine the forces acting on the charge. There are attempts to relate tension in the string to gravitational force and the electric force acting on the charge.

Discussion Status

The discussion is ongoing, with participants exploring the components of forces acting on the charge and how to relate them to the electric field. Some guidance has been offered regarding the equilibrium of forces, but no consensus has been reached on the next steps to solve the problem.

Contextual Notes

Participants are navigating the complexities of the problem setup, including the angle of deflection and the implications of the charge not hanging vertically. There is an emphasis on understanding the forces involved without providing a direct solution.

waleye262
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Homework Statement



A point charge of mass 0.069 kg and charge q = +5.89 µC is suspended by a thread between the vertical parallel plates of a parallel-plate capacitor.

If the angle of deflection is 22°, and the separation between the plates is 0.025 m, what is the potential difference between the plates?



Homework Equations



U = .5C*V^2

The Attempt at a Solution



I know the left has a higher potential energy because the mass is attracted toward the right?
 
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waleye262 said:

Homework Statement



A point charge of mass 0.069 kg and charge q = +5.89 µC is suspended by a thread between the vertical parallel plates of a parallel-plate capacitor.

If the angle of deflection is 22°, and the separation between the plates is 0.025 m, what is the potential difference between the plates?

Homework Equations



U = .5C*V^2

The Attempt at a Solution



I know the left has a higher potential energy because the mass is attracted toward the right?
Welcome to PF,

If the charge is displaced to the right, then the left would indeed be at a higher potential.

Can you start by determining the tension in the string?
 
The tension of the string is m*g= .68

I am still lost at how to find the the force that attracts it to the side.

would it be 5.89E-6 cos 22?
 
waleye262 said:
The tension of the string is m*g= .68
That would be correct if the string was hanging vertically, but that isn't the case is it?
 
no its not hanging vertically so mg=cos22?

I am sort of lost...
 
waleye262 said:
no its not hanging vertically so mg=cos22?
You're getting closer:

[tex]T\cos22 = mg[/tex]

Now since the mass is in equilibrium, what can you say about the horizontal forces acting on the mass?
 
alright so the force acting on the mass is the same as the tension force which is 0.729.

so would you use F=q(v/x)?
 
waleye262 said:
alright so the force acting on the mass is the same as the tension force which is 0.729.

so would you use F=q(v/x)?
Remember that you want the horizontal component of the force, not the vertical.
 

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