# Homework Help: Magnitude of Charges

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1. Sep 6, 2015

### pawlist

1. The problem statement, all variables and given/known data
I need to find the magbitude of charges

Lenght of string - 50 cm
mass of balls - 0.2 grams
theeta - 37 degrees

2. Relevant equations

K-8.99x10^9

3. The attempt at a solution

I found that half the distance between the balls is 15.9 cm but i dont know how to continue

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2. Sep 6, 2015

### 24forChromium

Okay, first, the balls will try to move toward one another because of the combined force of gravity and tension of the string, you should calculate the force vectors on the balls and figure out the horizontal component of the forces that drives the balls to move toward one another. This force, however, failed to move the balls because an equal and opposite force is acting on each ball that is pushing them away, and this force is the electromagnetic repulsion. You find the magnitude of that force and use the equation (I don't which one but you should have learnt it) to calculate the charge based on distance between charges and the amount of repulsion. Ask for clarification iyou want.

3. Sep 6, 2015

### pawlist

These are all of the available equations but i dont know which one to use.I uploaded an image

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4. Sep 6, 2015

### 24forChromium

force between point charge. You know the force and the distance, the charges should be a piece of cake to find.

5. Sep 6, 2015