# How Do You Calculate the Net Electrostatic Force on a Central Charge?

• keemosabi
In summary: Furthermore, you can use the Pythagorean Theorem to find the length of the other diagonal.In summary, the net electrostatic force acting on the charge at the center is +3.00 µC.
keemosabi

## Homework Statement

A charge of -3.00 µC is fixed at the center of a compass. Two additional charges are fixed on the circle of the compass (radius = 0.125 m). The charges on the circle are -4.00 µC at the position due north and +5.00 µC at the position due east. What is the magnitude and direction of the net electrostatic force acting on the charge at the center? Specify the direction relative to due east (0°).

I used Couloumb's Law to get the above picture, but what do I do now?

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Well, you seem to have found the resultant vector. That's the right idea. Don't you have a theorem from geometry that will let you figure its length from the other two? (Hint c^2 = a^2 + b^2)
The angle involves the arctangent.

AEM said:
Well, you seem to have found the resultant vector. That's the right idea. Don't you have a theorem from geometry that will let you figure its length from the other two? (Hint c^2 = a^2 + b^2)
The angle involves the arctangent.
How do I know the side length of the dotted line? It looks shorter than the 6.912 across from it.

keemosabi said:
How do I know the side length of the dotted line? It looks shorter than the 6.912 across from it.

Well, it seems to me that you have been too sloppy with your diagram. You will have a vector to the right representing the force of the charge to the East on the charge in the center and a vector down representing the force due to the charge to the north. You've computed these values. Make a scale drawing of the vectors and then use the parallelogram law for addition of the vectors. The diagonal of the parallelogram is the resultant. Here your parallelogram will be a rectangle and you can easily figure out its length.

## 1. What is electrostatic force direction?

Electrostatic force direction is the direction in which a charged particle will be pulled or pushed due to the presence of other charged particles nearby.

## 2. How is electrostatic force direction determined?

The electrostatic force direction is determined by the type and magnitude of the charges involved. Opposite charges will attract each other, while like charges will repel each other.

## 3. Does distance affect the direction of electrostatic force?

Yes, distance does affect the direction of electrostatic force. The force between two charges decreases as the distance between them increases, so the direction of the force will change as the distance changes.

## 4. Can electrostatic force direction be changed?

Yes, electrostatic force direction can be changed by altering the charge or distance of the objects involved. By changing the charges to be opposite or like, or by changing the distance between the charges, the direction of the force can be altered.

## 5. What is the relationship between electrostatic force direction and electric fields?

Electrostatic force direction is directly related to electric fields. Electric fields are created by charged particles and the direction of the electric field is the same as the direction of the electrostatic force that would be exerted on a positive test charge placed in the field.

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