Electric Force and Field Question:

Two point charges, +Q and -2Q, are placed 3 meters apart in a vacuum. Calculate the electric force between them.

Answer:

To calculate the electric force between two point charges, we can use Coulomb's Law formula:

where:

• F is the electric force between the charges,
• k is the electrostatic constant ($k = 8.99 \times 10^9 \, \text{N} \cdot \text{m}^2/\text{C}^2$),
• $q_1$ and $q_2$ are the magnitudes of the two charges, and
• r is the separation distance between the charges.

In this case, we have a positive charge, $Q$, and a negative charge, $-2Q$, placed 3 meters apart. Let's calculate the electric force using Coulomb's Law:

We can simplify this expression:

Rearranging and canceling units, we get:

Therefore, the electric force between the two charges is:

Note: This is the magnitude of the force. The direction of the force would depend on the sign of the charges.