A polystyrene component must not fail when a tensile stress of 1.25 MPa (180 psi) is applied. Determine the maximum allowable surface crack length if the surface energy of polystyrene is 0.50 J/m2 (2.86 × 10-3 in.-lbf/in.2). Assume a modulus of elasticity of 3.0 GPa (0.435 × 106 psi).