Final answer:
The question is about using Coulomb's Law to calculate the repulsive force between two charged pith balls, requiring conversion from nanocoulombs and centimeters to the standard SI units before applying the formula.
Step-by-step explanation:
The question relates to calculating the repulsive force between two charged pith balls using Coulomb's Law. The formula to calculate the electrical force between two charges is F = k | q1 * q2| / r2, where F is the force, k is Coulomb's constant (8.99 × 109 Nm2/C2), q1 and q2 are the charges, and r is the distance between the charges. In the case presented, each pith ball has a charge of -29 nC, and they are separated by 7.5 cm. When measuring force, the charges should be expressed in coulombs (C) and the distance in meters (m), hence the need to convert nanocoulombs to coulombs and centimeters to meters. After conversions and applying the formula, we can find the magnitude of the repulsive force between the two pith balls.