This is an example of Potential Energy being converted into Kinetic Energy.
When the charges are brought together the initial velocity of the charges is zero which means they do not possess any kinetic energy, but they are under the influence of electric field of the other charge which creates a potential energy in them which is released when they start moving and they bear the kinetic energy as the velocity is gained.
To know more about the conversion of energy used in this situation :
brainly.com/question/17264136
#SPJ4