Final answer:
The repulsive force between two charged pith balls can be calculated using Coulomb's Law. In this case, the force is -0.2675 N.
Step-by-step explanation:
The repulsive force between two charged pith balls can be calculated using Coulomb's Law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The formula for Coulomb's Law is F = k*q1*q2/d^2,
where F is the force, k is the proportionality constant (9.0 x 10^9 N*m^2/C^2), q1 and q2 are the charges, and d is the distance between the charges.
In this case, the force between the two pith balls with charges of -26 nC each and a distance of 5.5 cm apart can be calculated as:
F = (9.0 x 10^9 N*m^2/C^2) * (-26 x 10^-9 C)^2 / (0.055 m)^2
F = -0.2675 N
Therefore, the repulsive force between the two pith balls is -0.2675 N.