HUKUM COULOMB DUA MUATAN LISTRIK KELAS 12

Summary

In this video, the focus is on explaining the Coulomb force and its application in various scenarios involving electric charges. The script walks through the concepts of attractive and repulsive forces between charges, using examples to calculate the magnitudes and directions of these forces. Specific problems are discussed, including the forces acting on charge q2 in a system of charges q1 and q3, as well as how to apply Coulomb's law to solve for unknown values. The content provides both theoretical insights and practical problem-solving techniques to understand the behavior of electric forces.

Takeaways

• 😀 The script discusses Coulomb force calculations between charges in various configurations.
• 😀 It explains the force interactions when a particle with a positive charge (q2) is placed between two charges (q1 and q3), both of which are negative.
• 😀 The forces between charges q2 and q1 (f21) and q2 and q3 (f23) are both attractive since opposite charges attract.
• 😀 The resultant force on charge q2 is calculated by considering both the magnitude and direction of the forces from q1 and q3.
• 😀 The formula for Coulomb's force, F = k * (q1 * q2) / r^2, is used to calculate the individual forces (f21 and f23).
• 😀 The vector direction of force f21 is towards charge q1, while the direction of f23 is towards charge q3.
• 😀 The magnitude of the Coulomb forces between the charges is calculated step by step using values for charge and distance.
• 😀 The script explains that forces are vector quantities, meaning they have both magnitude and direction, and they combine using vector addition.
• 😀 The angle between the forces from q1 and q3 on q2 is considered to form an equilateral triangle, leading to a force vector calculation involving cos(120°).
• 😀 The final calculation gives the magnitude of the resultant force on q2, which is approximately 3.83 N, directed towards charge q1.
• 😀 The script also demonstrates how to solve for the unknown distance (x) in a different charge configuration, where Coulomb forces between multiple charges are balanced.

Q & A

What is the initial setup of the charges in the problem?

In the problem, charge q2 is placed in the middle of charges q1 and q3. Charge q1 and q3 are both negative, while charge q2 is positive.

What is the direction of the force experienced by q2 due to q1 and q3?

The force between q2 and q1 is attractive because q1 is negative and q2 is positive. Similarly, the force between q2 and q3 is also attractive, with both forces pointing towards their respective charges.

How do we calculate the magnitude of the force between q2 and q3?

The force between q2 and q3 (f23) is calculated using Coulomb's Law: f23 = k * |q2 * q3| / r23^2, where k is Coulomb's constant, q2 and q3 are the charges, and r23 is the distance between them.

How do we calculate the magnitude of the force between q2 and q1?

The force between q2 and q1 (f21) is calculated similarly using Coulomb's Law: f21 = k * |q2 * q1| / r21^2, where r21 is the distance between q2 and q1.

What is the method to determine the resultant force on q2?

The resultant force on q2 is calculated by finding the vector sum of the forces f21 and f23. Since the forces are along different directions, we use the Pythagorean theorem to combine them.

How is the direction of the resultant force determined?

The direction of the resultant force is determined by the angles formed between the forces f21 and f23. Since both forces are attractive and point towards the respective charges, the direction of the resultant force is towards the negative x-axis, approaching charge q1.

Why do we use the cosine of 120 degrees in the calculation of the resultant force?

The cosine of 120 degrees is used because the angle between the two forces, f21 and f23, is 120 degrees. Since these forces are not along the same line, we need to account for the angle between them using the cosine rule in vector addition.

What is the final magnitude of the resultant force on q2?

The final magnitude of the resultant force on q2 is calculated to be approximately 3.74 N, after considering the vector addition of the forces f21 and f23.

What is the purpose of calculating the angle between the forces?

The angle between the forces is crucial for determining the direction and magnitude of the resultant force. It allows us to properly apply the cosine rule in the vector addition of the forces, as they are not aligned along a single axis.

How does the Coulomb force depend on the distance between charges?

The Coulomb force is inversely proportional to the square of the distance between the charges, as indicated by Coulomb's Law: f = k * |q1 * q2| / r^2. This means that as the distance between charges increases, the force decreases.