The independent variables would be time and he dependent variables would be the distance traveled. Time is always independent because it is not reliant on something else when something happens over a period of time.
Increase in speed or rate
The electrostatic force between two charged objects is given by

where
k is the Coulomb's constant
q1 is the charge of the first object
q2 is the charge of the second object
r is the separation between the two objects
In our problem:



So if we plug these numbers into the equation, we can find the electrostatic force between the two objects: