It is desired to produce and aligned carbon fiber-epoxy matrix composite having a longitudinal tensile strength of 600 MPa. Calculate (a) the critical fiber length, and (b) the volume fraction of fibers necessary if (1) the average fiber diameter is 0.028 mm, (2) the average fiber length is 2.2 mm, (3) the fiber fracture strength is 5000 MPa, (4) the fiber-matrix bond strength is 19 MPa, (5) the matrix stress at fiber failure is 16.0 MPa.