1. Understand the Concepts

* Coulomb's Law: This law describes the electrostatic force between charged objects. It states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

* Electrostatic Force: The force of attraction or repulsion between charged objects. Like charges repel, and opposite charges attract.

2. Formula

The formula for Coulomb's Law is:

```

F = k * (q1 * q2) / r^2

```

Where:

* F = electrostatic force (in Newtons, N)

* k = Coulomb's constant (approximately 8.98755 × 10^9 N⋅m^2/C^2)

* q1 and q2 = magnitudes of the charges (in Coulombs, C)

* r = distance between the charges (in meters, m)

3. Convert Units

* Distance: 5.0 cm = 0.05 m

4. Plug in the Values

```

F = (8.98755 × 10^9 N⋅m^2/C^2) * (1.6 × 10^-10 C) * (1.6 × 10^-10 C) / (0.05 m)^2

```

5. Calculate the Force

```

F ≈ 9.2 × 10^-6 N

```

6. Interpretation

The force between the two balloons is approximately 9.2 × 10^-6 Newtons. Since both balloons have the same negative charge, the force is repulsive (they will push each other away).