Coulomb's Law for Discrete Charge Distributions

🔖 Topics

• Electric charge
• Coulomb’s law
• Superposition

🎯 Objectives

• Describe the two types of electric charge
• Calculate the forces on point charges using Coulomb’s law
• Utilize superposition to calculate the net force from multiple point charges

📋 Sequence

• Electric charge
  • Elementary charge $e=1.6\times 10^{-19}C$
• Coulomb’s law examples
  • Force between two point charges along the x-axis
  • Force between two point charges positioned at arbitrary points in the xy-plane
  • Force on a point charge from two other point charges
  • Net force on a point charge at the center of a square
  • Net force on a point charge at the center of an equilateral triangle

🖥️ Animations, Simulations, Activities

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📝 Practice Problems

1. Two point charges, each with a charge of +1.5 mC are separated by a distance of 5.75 m. What is the magnitude of the electric force between the point charges? Do they attract or repel each other?

2. A point charge of +15 $\mu C$ is located at the point (1 m, 2 m). Another point charge of -15 $\mu C$ is located at the point (0 m, -5 m). What is the electric force acting on the negative point charge from the positive one?

3. A charge of 10 $\mu C$ is positioned at the origin while another charge of -30 $\mu C$ is positioned at the point (5 cm, 0 cm). Where around the two points (if anywhere) is the net electric force on a positive point charge equal to zero?

✅ Partial Solutions

1. 612.48 N, Repel
2. 0.0405 N, $81.87^{\circ }$
3. (-6.83 cm, 0 cm)

📘 Connected Resources

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