The longitudinal vibrations of a semi-infinite flexible rod satisfy the wave equation utt = c2uxx for x > 0. Assume that the end x = 0 is free (ux = 0); it is initially at rest but has a constant initial velocity V for a < x < 2a and has zero initial velocity elsewhere. Plot u versus x at the times t = 0, a/c, 3a/2c, 2a/c, and 3a/c