Final answer:
To maintain the same force when the distance between two charges is doubled, one of the charges must be increased by a factor of 4 according to Coulomb's law.
Step-by-step explanation:
When two charges separated by a distance r experience an attractive force and that distance is increased, the force between the charges will decrease unless the magnitude of one or both charges is increased. According to Coulomb's law, the electrostatic force (F) between two charges is directly proportional to the product of their magnitudes (q1*q2) and inversely proportional to the square of the distance between them (r^2). Therefore, to keep the force the same when the distance is doubled, one of the charges must be increased by a factor of 4.