Answer:
The force between the two balloons can be calculated using Coulomb's law:
F = k * (q1 * q2) / r^2
Substituting the given values, we get:
F = 9 × 10^9 * (5 × 10^-9 * (-4 × 10^-9)) / (0.025)^2
F ≈ -1.44 × 10^-4 N
The force between the two balloons is approximately -1.44 × 10^-4 N. The negative sign indicates that the force is attractive.