Size of Force between two Point Charges

In summary, the question involves calculating the force between two point charges, +2.0 microC and -0.35 microC, separated by a distance of 4.0 x10-4 m. Using the equation F = 1/(4 pi ε0) x (q1 x q2 / r-squared), the size of the force is found to be -3.9 x 10 (power of 4) N. The direction is determined to be attractive, as the charges have opposite signs. Therefore, the force between the charges is -3.9 x 10 (power of 4) N.
  • #1
ZedCar
354
1

Homework Statement


A point charge of +2.0 microC is separated from a second point charge of -0.35 microC by a distance of 4.0 x10-4 m. Calculate the size of the force that each charge exerts on the other and its direction. (Assume 1/4 pi ε0 = 9.0 x109 m F-1)


Homework Equations



F = 1/(4 pi ε0) x (q1 x q2 / r-squared)


The Attempt at a Solution



I get an answer of -3.9 x 10 (power of 4) N

The question asks for the direction. So by stating the -'ve before the 3.9 am I indicating the direction?

Or should I state the answer is +3.9 x 10 (power of 4) N in a particular direction?

Thank you
 
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  • #2
You've got the size of the force down. As for the direction: you have opposite charges, which means they attract one another. So your first answer (the negative one) is the one you should use.
 
  • #3
Ok, thanks very much for the help Cryxic. It's very much appreciated. :smile:
 

1. What is the formula for calculating the size of force between two point charges?

The formula for calculating the size of force between two point charges is F = k * (q1 * q2) / r2, where F is the force in Newtons, k is the Coulomb's constant (9 x 109 Nm2/C2), q1 and q2 are the magnitudes of the two point charges in Coulombs, and r is the distance between the two charges in meters.

2. How does the distance between two point charges affect the size of force?

The size of force between two point charges is inversely proportional to the square of the distance between them. This means that as the distance between the charges increases, the force between them decreases.

3. What is the relationship between the magnitude of the point charges and the size of force?

The size of force between two point charges is directly proportional to the product of the magnitudes of the two charges. This means that as the magnitudes of the charges increase, the force between them also increases.

4. How do positive and negative charges affect the size of force between them?

The force between two charges depends on their magnitudes and the distance between them, regardless of whether they are positive or negative. However, opposite charges (positive and negative) attract each other, while like charges (positive and positive, or negative and negative) repel each other, resulting in a larger or smaller force between them.

5. Can the size of force between two point charges ever be zero?

Yes, the size of force between two point charges can be zero if the two charges have the same magnitude and are placed at the same distance from each other. This is because the force formula includes a division by the square of the distance, which would result in a zero force if the distance is also zero.

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