An elastic bar has a static displacement due to an applied axial load F. The force is suddenly removed, resulting in free oscillations of the bar. Derive the expression governing the displacement u(x, t) of a particle along the axis of the bar.
a. Specify the governing differential equation as well as all boundary and initial conditions necessary to solve for u(x, t).
b. Nondimensionalize the problem by introducing x* = x/L t* = t/T , where T is to be chosen for convenience.