F = k * (q1 * q2) / r²
Where:
* F is the electrical force (in Newtons, N)
* k is Coulomb's constant, approximately 8.98755 × 10⁹ N⋅m²/C²
* q1 and q2 are the charges of the two objects (in Coulombs, C)
* r is the distance between the centers of the two charges (in meters, m)
Here's how to use the formula:
1. Identify the charges: Determine the magnitude and sign of each charge (e.g., +2 μC, -5 nC).
2. Calculate the distance: Measure the distance between the centers of the charges.
3. Plug in the values: Substitute the charges and distance into Coulomb's Law formula.
4. Calculate the force: Solve the equation to find the magnitude of the electrical force.
Important points to remember:
* Direction of the force: The force is attractive if the charges have opposite signs (one positive and one negative) and repulsive if they have the same sign (both positive or both negative).
* Units: Make sure to use consistent units (Coulombs for charge, meters for distance).
* Scalar vs. vector: Coulomb's Law gives the magnitude of the force. To determine the direction, consider the signs of the charges.
Example:
Two point charges, q1 = +3 μC and q2 = -2 μC, are separated by a distance of 0.5 m. Calculate the electrical force between them.
1. Charges: q1 = +3 μC = 3 × 10⁻⁶ C, q2 = -2 μC = -2 × 10⁻⁶ C
2. Distance: r = 0.5 m
3. Plug in: F = (8.98755 × 10⁹ N⋅m²/C²) * [(3 × 10⁻⁶ C) * (-2 × 10⁻⁶ C)] / (0.5 m)²
4. Calculate: F = -0.2157 N
Therefore, the electrical force between the two charges is 0.2157 N, attractive since the charges have opposite signs.
