An electron is projected with an initial speed $v_{i}=3.2 \times 10^{5} \mathrm{m} / \mathrm{s}$ directly toward a very distant proton that is at rest. Because the
proton mass is large relative to the electron mass, assume that the
proton remains at rest. By calculating the work done on the electron by the electrostatic force, determine the distance between the
two particles when the electron instantaneously has speed 2$v_{i .}$