Why must charge be moved without acceleration in potential energy definition?

[Hardik Batra]

Electric potential energy of a charge q at a point in an electric field due to any charge configuration as the work done by the external force in bringing the charge q from infinity to that point without any acceleration..


In this definition, why charge is moved without any acceleration?

 

[jtbell]

Acceleration changes the velocity, and therefore also the kinetic energy. The work done on the charge equals the change in potential energy only if the change in kinetic energy is zero.