Calculating Potential Difference and Work in a Parallel Plate Capacitor

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SUMMARY

The discussion focuses on calculating the potential difference and work involved in a parallel plate capacitor with an initial area of 1 m² and a spacing of 10 cm, charged to 1500 V. When the plates are separated to 11 cm, the potential difference increases due to the constant charge. The work required to pull the plates apart is calculated using the formula W=F*dr, where the force is 10 N greater than the force needed to maintain the separation. The challenge arises in determining the velocity of the plates without knowing their mass, highlighting the need for additional information to solve part c of the problem.

PREREQUISITES
  • Understanding of parallel plate capacitor principles
  • Familiarity with electric potential difference calculations
  • Knowledge of work-energy principles in physics
  • Basic kinematics and force equations
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  • Study the relationship between charge, capacitance, and potential difference in capacitors
  • Learn how to apply the work-energy theorem in electrostatics
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  • Investigate the role of mass in determining acceleration and velocity in physics problems
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Homework Statement



The area of the plates of a parallel plate capacitor is 1 m2, the spacing between the plates is 10 cm, the potential difference between the plates is 1500 V. After beign charged, the plates are disonnected electrically from the surroundings. The plates are then pulled farther apart so that the new spacing is 11 cm.


a. What is now the potential difference between the plates?
b. How much work is required to pull the plates apart?
c. Assume that the pulling apart of the plates is accomplished by a constant force of 10 N more than the force required to keep the plates apart. How fast are the plates moving away from one another when the plates are separated by 11 cm?


Homework Equations




W=F*dr

The Attempt at a Solution



The first parts are doable, if, like I'm assuming, the charge is going to be constant. However, without a mass given, I can't see how part c is going to work out. I figured it'd have something to do with energy conservation or kinematics, but I don't know how to solve for v without an m to put into the energy equation, or to figure the acceleration. Any help is appreciated.
 
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You're right. You need the mass of the plates to answer the question.
 

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