It is desired to produce an aligned carbon fiber-epoxy matrix composite having a 0.18 volume fraction of fibers. calculate (a) the critical fiber length, and (b) the longitudinal strength of the composite (in mpa), assuming the following: (1) the average fiber diameter is 0.017 mm, (2) the average fiber length is 7.0 mm, (3) the fiber fracture strength is 3.2 gpa, (4) the fiber-matrix bond strength is 89 mpa, (5) the matrix stress at fiber failure is 13.5 mpa, (6) the matrix tensile strength is 65 mpa.