Questions:

Regard as two positively charged particles at a separation of 2.0 cm. One of the charged particles is shifting toward the other charged particle with a speed of 15 m/s. No forces apart from for the Coulomb force of repulsion (as well known as the electrostatic force of repulsion) act on either particle. Is this circumstances the one just described actually possible?

Answer:

Obviously it is possible for a positively charged particle at some instant in time to have a velocity directed at another positively charged particle. There is a repulsive force however force directly determines acceleration not velocity. The force just makes it consequently that the velocity in this case is decreasing. To articulate that a positively charged particle can never be approaching another positively charged particle would be like saying that a free ball can never be going upward near the surface of the earth. In both cases history matters however the details of that history are not relevant. Something in the past must have affect that particle to have some velocity toward the other positively charged particle.

What keeps it going? The best respond is "nothing." The natural propensity of a particle in motion is to keep on going in the same direction at the same speed (Newton's 1st Law). It does not need anything to keep it going forward. The reality that there is a force in the direction opposite to the particle's velocity will indeed cause the particle to deviate from its constant speed behaviour. It makes it consequently that as time goes by the particle slows down. An okay alternate answer to the question as to what keeps the particle moving is its inertia.