Finding the x-component of a force using Coulomb's Law

Click For Summary
SUMMARY

The discussion focuses on calculating the x-component of the force between two point charges using Coulomb's Law. The initial force exerted by charge q1 (-2.9 μC) on charge q2 (5 μC) was determined to be -17.64 N. After displacing q2 by 2.4 cm in the positive y-direction, the new force was calculated to be -16.37 N, but the x-component was incorrectly derived as -11.58 N due to an assumption of a 45-degree angle. The correct approach involves accurately determining the angle based on the new positions of the charges.

PREREQUISITES
  • Coulomb's Law (F = k (q1q2)/(r^2))
  • Pythagorean theorem for distance calculation
  • Trigonometric functions (specifically cosine)
  • Understanding of electric charge units (microcoulombs)
NEXT STEPS
  • Review the derivation of Coulomb's Law and its applications
  • Learn how to calculate forces in two dimensions using vector components
  • Study the implications of charge displacement on force calculations
  • Explore trigonometric functions in physics, particularly in force resolution
USEFUL FOR

Students studying electrostatics, physics educators, and anyone involved in solving problems related to electric forces and charge interactions.

cherrymilk
Messages
5
Reaction score
0

Homework Statement


(1) A point charge q1 = -2.9 μC is located at the origin of a co-ordinate system. Another point charge q2 = 5 μC is located along the x-axis at a distance x2 = 8.6 cm from q1.

The answer to this was -17.64N.

(2) Charge q2 is now displaced a distance y2 = 2.4 cm in the positive y-direction. What is the new value for the x-component of the force that q1 exerts on q2?

Homework Equations


Coulomb's Law: F = k (q1q2)/(r^2)


The Attempt at a Solution


Seeing that q2's position had changed, I calculated the new force exerted using Coulomb's Law. I used 9*10^9 for k, and using the Pythagorean theorem, I calculated the new distance between the charges, which I got to be 0.089. After using Coulomb's Law, I got an answer of -16.37N. To find the x-component, I multiplied this value by cos(45), giving me a final answer of -11.58. This, however, is apparently incorrect and I'm confused as to why.

Any help would be appreciated!
 
Physics news on Phys.org
Why did you chose 45 degrees as the angle?
 
OtherWindow said:
Why did you chose 45 degrees as the angle?

Ah, I see what I did wrong. I just assumed that because they had drawn the line they way they did in the figure, the angle was 45 degrees. Silly mistake, thanks for that!
 

Similar threads

Find the magnitude of the electric force from 3 charges at vertices of a cube
  • · Replies 17 ·
Replies
17
Views
2K
Calculate electric force using Coulomb's law (vector components are the struggle)
  • · Replies 3 ·
Replies
3
Views
1K
Dependence of Coulomb's law on the medium
  • · Replies 8 ·
Replies
8
Views
3K
Coulomb's law to find electric field for charge density function
  • · Replies 11 ·
Replies
11
Views
1K
Possible variables for Coulombs Law?
  • · Replies 5 ·
Replies
5
Views
2K
How to find distance between 2 charges, with no force given?
  • · Replies 2 ·
Replies
2
Views
2K
Coulomb's Law in 3D: Find Electric Force & Field
  • · Replies 2 ·
Replies
2
Views
3K
Calculating Coulomb Forces Between Point Charges
  • · Replies 5 ·
Replies
5
Views
6K
Coulomb's law vs Electric Field
  • · Replies 12 ·
Replies
12
Views
5K
Three charges located on a straight line
  • · Replies 7 ·
Replies
7
Views
10K