Calculating Charge on Two Pith Balls Using Coulomb's Law | Homework Help

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Homework Help Overview

The problem involves calculating the charge on two pith balls using Coulomb's Law, given their masses and the angle of separation when suspended. The context is centered around electrostatics and force equilibrium.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationship between the forces acting on the pith balls, with one participant expressing uncertainty about finding acceleration and others suggesting a focus on force equilibrium and the use of free-body diagrams.

Discussion Status

The discussion is active, with participants exploring different aspects of the problem. Some guidance has been provided regarding the importance of considering all forces acting on the balls and the utility of free-body diagrams.

Contextual Notes

There is a mention of the balls remaining at rest, which implies a need to consider static equilibrium in the analysis. The original poster's approach to finding acceleration is questioned, indicating a potential misunderstanding of the problem setup.

Hannahj1
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Homework Statement


The charge on two pith balls can be calculated by knowing their masses and observing the angle of separation between the balls.
If both balls are equally charged and they are suspended by strings that are 1.0 m long, calculate that charge.

Homework Equations


F = k q Q / d^2

The Attempt at a Solution


fnet=kqQ/d^2
ma=kq^2/d^2 (both q's are the same)
Im a bit stuck here because i don't know how to find the acceleration. Thank you!
 

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Hannahj1 said:
Im a bit stuck here because i don't know how to find the acceleration.
The balls remain at rest.
 
Why acceleration?

Why don't you try equilibrium of forces?
 
Have you drawn a free body diagram on either of the balls, or do you feel you have advanced beyond the point where you need to use FBDs?

Chet
 
Hannahj1 said:
fnet=kqQ/d^2

This is not Fnet, because the electric force is not the only one acting on each ball. Your first step should be to choose one ball (either one will work, so you can toss a coin or something), then identify all the forces that act on it and draw a free-body diagram for it as Chet asked for.
 

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