Charge on pith ball between two plates

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SUMMARY

The discussion focuses on calculating the charge on a pith ball suspended between two plates with a potential difference of 480 V and a plate separation of 6 centimeters. The mass of the pith ball is specified as 40 milligrams, and the string hangs at an angle of 20 degrees to the vertical. The correct charge on the pith ball is determined to be 1.8 x 10^-8 C, derived using the equations F=ma, E=F/q, and V=E/d. The user expressed confusion regarding their calculations, indicating a misunderstanding of unit conversions, particularly between grams and milligrams.

PREREQUISITES
  • Understanding of basic physics concepts such as force, mass, and acceleration (F=ma).
  • Familiarity with electric fields and the relationship between force, charge, and electric field strength (E=F/q).
  • Knowledge of voltage and its relation to electric field and distance (V=E/d).
  • Ability to perform unit conversions, specifically between milligrams and grams.
NEXT STEPS
  • Review the principles of electrostatics, focusing on charge interactions and electric fields.
  • Practice solving problems involving forces on charged objects in electric fields.
  • Learn about unit conversions in physics, particularly between different metric units.
  • Explore the concept of equilibrium in physics, particularly in systems involving angles and forces.
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Students studying physics, particularly those focusing on electrostatics and mechanics, as well as educators looking for examples of problem-solving in these areas.

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Homework Statement



The mass of the ball is 40 milligrams, the applied potential difference is 480 V and the plate separation is 6 centimeters. If the string hangs at an angle of 20 degrees to the vertical, determine the charge on the pith ball.

Homework Equations


[/B]
F=ma
E=F/q
V=E/d

The Attempt at a Solution



This is my work shown to the end, although the answer is wrong I'm not sure what I missed, and any help would be greatly appreciated. The answer is supposed to be 1.8x10^-8, but I'm not sure how to get there.
http://imgur.com/a/sgRUX
eiUz7DD.png
 
Last edited by a moderator:
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fizzicmaniac said:
V=E/d
Really?
 
Also:
fizzicmaniac said:
The mass of the ball is 40 milligrams

upload_2016-12-17_6-6-53.png


Grams are not milligrams!
 

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