Meriam, Kraige & Bolton — Kinematics of Particles: Problem 2_57

2/57 Electrons are emitted at A with a velocity \(u\) at the angle \(\theta\) into the space between two charged plates. The electric field between the plates is in the direction \(E\) and repels the electrons approaching the upper plate. The field produces an acceleration of the electrons in the \(E\)-direction of \(eE/m\), where \(e\) is the electron charge and \(m\) is its mass. Determine the field strength \(E\) which will permit the electrons to cross one-half of the gap between the plates. Also find the distance \(s\).