An electron of mass \(m\) and charge magnitude \(e\) is released from rest in a uniform electric field of magnitude \(E\) directed to the right. The electron accelerates under the influence of the electric field through a distance \(d\). What is the change in electric potential energy \(\Delta U\) of the electron-field system after the electron travels distance \(d\), and what is the speed \(v\) of the electron at that point?