It is desired to produce an aligned carbon fiber-epoxy matrix composite having a 0.11 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 0.014 mm, (2) the average fiber length is 5.2 mm, (3) the fiber fracture strength is 3.2 GPa, (4) the fiber-matrix bond strength is 80 MPa, (5) the matrix stress at fiber failure is 16.5 MPa, (6) the matrix tensile strength is 71 MPa. (a) mm (b) MPa