3. Consider the railgun system below. The bar has width w, mass m, and current lo provided by the DC current source, and starts at rest at y = 0. There is an external magnetic field B, and the rails are of length 1 measured from the bar's initial position. Assume no gravity or air resistance effects. Think of the xy-plane as a flat tabletop. (a) Draw the position and kinetic energy of the bar over time, including what you expect happens just outside the railgun. Provide the expressions. (Two plots, two expressions) Io B W X No gravity 1 Vy KE Inside railgun vy(t) = Outside railgun t = ? KE(t) = ? t (b) Suppose someone applies the same frequency AC source to generate both Io, B. Is it possible to get the bar out of the railgun? If so, provide some way to estimate its final kinetic energy. Either way, justify. (Short answer)