Coulomb's Law (5 of 7) Force from Three Charges in a Straight Line

TL;DR

An explanation of how to solve a Kum's law problem involving the net force between three charges on a straight line.

Transcript

okay in today's video we are going to do a kums law problem and in this problem we have three charges and all three charges lie on a straight line we have in this situation q1 which is minus 16 micrum we have Q2 which is plus 6 micrum and we have Q3 which is minus 8 micrum now we are going to determine the net force the magnitude and the direction ... Read More

Key Insights

• 👮 Kum's law can be used to calculate the magnitudes of forces between charged particles.
• 🈂️ The direction of the force between charges can be determined by comparing the charges' signs.
• 🧑‍🏭 The net force on a particle is the vector sum of the individual forces acting on it.

Questions & Answers

Q: How is the direction of the forces determined on Q3 from Q1 and Q2?

The direction of the force on Q3 from Q1 is to the right because both charges are negative and repel each other. The direction of the force on Q3 from Q2 is to the left because Q2 is positive and attracts Q3, which is negative.

Q: How are the magnitudes of the forces calculated?

To calculate the magnitude of the force on Q3 from Q1, Kum's law is used with Kum's constant, the charge of Q3, the charge of Q1, and the distance between them. The magnitude of the force on Q3 from Q2 is calculated using the same formula but with the charge of Q2.

Q: What is the net force on Q3 from both Q1 and Q2?

The net force on Q3 is calculated by adding the force from Q1 and the negative force from Q2. The negative sign is used to account for the opposite direction of the force from Q2.

Q: What does the minus sign in the net force value mean?

The minus sign indicates that the net force on Q3 is to the left direction. It does not mean a negative force value; it represents the direction of the force.

Summary & Key Takeaways

• The problem involves three charges on a straight line: Q1 is -16 micrum, Q2 is +6 micrum, and Q3 is -8 micrum.

• The direction of the force on Q3 from Q1 is to the right, while the direction of the force on Q3 from Q2 is to the left.

• Using Kum's law and Kum's constant, the magnitudes of the forces are calculated to be 1.42 Newtons and 4.80 Newtons, respectively.