Need help using Coulomb's Law to find unkown charge

In summary, the problem involves finding the value of q1 in a static equilibrium system where q2 is already known. The solution involves equating the forces on q2 from q1 and the center charge, and solving for q1. It is not necessary to assume that q1 and q2 are equal.
  • #1
azsktbrdr
3
0
Hi, the problem states the following. "Charge q2 is in static equilibrium. What is q1?"

I've attached the image of the problem I'm working on. From the looks of this it should be quick and simple it seems, but I am having a tough time with it. I would appreciate any help you can offer.

With q2 being in static eq., I thought that meant that all forces on q2 sum to zero, so I tried to add the forces from q1 and the center charge up and set equal to zero and solve for q1, but I'm not sure if this is right. Also, I put in the assumption that q1 and q2 are equal and I don't know if that is true, either. :cry:
 

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  • #2
You do not need to assume that q1 and q2 are equal. Basically, you just need to write down the force exerted on q2 by q1 and the center charge respectively. Equate these two expressions and solve for q1.


Kenneth
 
Last edited:
  • #3
Kenneth,

Thanks for the help. I can't believe I didn't notice that the q2's would cancel when you equate the two. Yikes, I need to get to bed before I do any more damage :zzz:
 

1. What is Coulomb's Law?

Coulomb's Law is a fundamental law in physics that describes the electrostatic interaction between two charged particles. It states that the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

2. How do I use Coulomb's Law to find an unknown charge?

To use Coulomb's Law to find an unknown charge, you need to know the values of the other variables in the equation. These include the distance between the two charges, the magnitude of the other charge, and the constant of proportionality. Once you have these values, you can rearrange the equation to solve for the unknown charge.

3. What units are used in Coulomb's Law?

The units used in Coulomb's Law are typically in SI units, specifically coulombs for charge, meters for distance, and newtons for force. However, you can use any consistent set of units as long as they are used for all variables in the equation.

4. Can Coulomb's Law be used for point charges only?

No, Coulomb's Law can be used for any types of charges, including point charges, spherical charges, and line charges. The equation may be slightly modified depending on the type of charge, but the fundamental principle remains the same.

5. What are some real-world applications of Coulomb's Law?

Coulomb's Law has many real-world applications, including understanding the behavior of charged particles in electric fields, designing electronic circuits, and predicting the behavior of atoms and molecules. It is also used in fields such as engineering, chemistry, and astronomy.

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