How Do You Calculate the Charge on Spheres with Unequal Charges?

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Homework Help Overview

The problem involves calculating the charges on two spheres that attract each other with a known force, given that one sphere has twice the charge of the other and they are of opposite signs. The context is rooted in electrostatics, specifically Coulomb's law.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss the application of Coulomb's law and the relationship between the charges. There is a question about whether the correct equation is being used and the importance of unit conversion from centimeters to meters. Some participants explore the implications of solving for one charge and then deriving the other.

Discussion Status

The discussion is active, with participants providing guidance on solving for the charge and addressing unit conversion. There is acknowledgment of the simplicity of the approach once the correct steps are clarified, though some uncertainty remains regarding the initial setup and understanding of the problem.

Contextual Notes

One participant notes missing class sessions, which may contribute to their confusion about the problem. There is an emphasis on ensuring all variables are correctly accounted for in the equations used.

LampMan
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Homework Statement


two charged spheres 4 cm apart attract each other with a force of 1.2x10^-9 . determin the magnitude of the charge on each if one has twice the charge (of the opposite sign) as the other.

Homework Equations



Fe = KQq/r^2

The Attempt at a Solution



well you are only given Fe and r, plus the info that Q is = to (2)q and k = 9.0x10^9 so I am stumped after this step

1.2x10^-9 = (9.0x10^9)(2)qq/16
 
Last edited:
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In your equation everything is a number except for q. Can you solve it for q? Also, you forgot to convert cm to meters.
 
could it possibly be that I am using the wrong equatiom? and should be using E(force intensity) = kq/r^2 instead of coulombs law??

edit: yes i forgot to convert haha good call..but yea the fact that I am finding two charges throws me off...so would just solving for one q give me the charge I am looking for, then just double it to get the 2nd charge?
 
Correct. Find q then double it. It is that simple.
 
aha well I've mised 2 of 2 classes on this unit so i can't believe it was that easy now that i see it ahhh well thanks a lot
 

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