Coulomb's Law (Finding the force due to two other charge, not only one)

In summary, using Coulomb's Law with a constant k of 9.0 x 10^9, the electric force on 10 micro Coulomb due to other charges is 54N. This is found by subtracting the force of 90N on 10 micro Coulomb from the force of 36N on 2 micro Coulomb. It is important to pick an origin and determine the x- and y-components of the force on the particle, then add them together to find the total force vector.
  • #1
daimlerpogi
5
0

Homework Statement


In the figure below, determine (a) the electric force on 10 micro Coulomb due to other charges, and (b) the electric force on 2 micro Coulomb due to other charge


Homework Equations


Coulomb's Law

Fe = kq1q2/D²
k = 9.0 x 10^9

The Attempt at a Solution



I really don't know what to do since there are three charges and I should get the Fe due to other two charges. Should I get the Fe in each charge then subtract it? :confused:

(a)
10 and 2

Fe = 9x10^9(10x10^-6)(2x10^-6) / 0.005
Fe = 36N

Fe = 9x10^9(10x10^-6)(5x10^-6) / 0.005
Fe = 90N

Fe of 10micro Coulomb = 90 - 36 = 54N?

I really don't know, but I'm trying my best.
 

Attachments

  • ImageEE.JPG
    ImageEE.JPG
    8.9 KB · Views: 554
Last edited:
Physics news on Phys.org
  • #2
Pick an origin first. It doesn't really matter where you place it, but I usually place it on the particle that you are trying to determine the E field for. This is a two dimensional problem, so determine the x- and y- components of the force on the particle due to each individual particle. To find the total force on the particle, add the x- and y-components together (principle of superposition); this gives you the force vector acting on the particle.
 
  • #3


Good effort in attempting to solve this problem. You are correct in using Coulomb's Law to calculate the electric force between two charges. However, in order to calculate the total force on a charge due to multiple other charges, we need to use vector addition. This means that we need to calculate the force due to each individual charge and then add them together using vector addition.

For part (a), the force on 10 micro Coulomb due to the other two charges would be:

Fe = 9x10^9(10x10^-6)(2x10^-6) / 0.005 = 36N

Fe = 9x10^9(10x10^-6)(5x10^-6) / 0.005 = 90N

Adding these two forces together using vector addition, we get:

Fe = √(36^2 + 90^2) = 96.8N

So the total electric force on 10 micro Coulomb due to the other two charges is 96.8N.

For part (b), we can follow the same process to calculate the force on 2 micro Coulomb due to the other two charges. The force due to each individual charge would be:

Fe = 9x10^9(2x10^-6)(10x10^-6) / 0.005 = 36N

Fe = 9x10^9(2x10^-6)(5x10^-6) / 0.005 = 18N

Adding these two forces together using vector addition, we get:

Fe = √(36^2 + 18^2) = 40.2N

So the total electric force on 2 micro Coulomb due to the other two charges is 40.2N.

Remember to always use vector addition when calculating the total force on a charge due to multiple other charges. Keep up the good work!
 

1. What is Coulomb's Law?

Coulomb's Law is a fundamental law of electrostatics that describes the force between two point charges. 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 you calculate the force between two charges using Coulomb's Law?

The formula for calculating the force between two charges is F = (k * q1 * q2) / r2, where F is the force in Newtons, q1 and q2 are the magnitudes of the charges in Coulombs, r is the distance between the charges in meters, and k is the Coulomb's constant (9 x 109 N*m2/C2).

3. What is the direction of the force between two charges?

The force between two charges is a vector quantity, meaning it has both magnitude and direction. The direction of the force is along the line connecting the two charges, and it is attractive if the charges are opposite in sign and repulsive if they are the same sign.

4. Can Coulomb's Law be applied to non-point charges?

Coulomb's Law is only valid for point charges, which are charges that are infinitely small and have no physical dimensions. However, it can be used as an approximation for non-point charges if the distance between the charges is much larger than their size.

5. How does the force between two charges change as the distance between them increases?

According to Coulomb's Law, the force between two charges decreases as the distance between them increases. This is because the inverse square relationship means that the force decreases much more rapidly than the distance increases. Therefore, the force becomes weaker as the charges move further apart.

Similar threads

Replies
17
Views
858
  • Introductory Physics Homework Help
Replies
2
Views
3K
  • Introductory Physics Homework Help
Replies
11
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
Replies
10
Views
7K
  • Introductory Physics Homework Help
Replies
6
Views
7K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
2K
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
Back
Top