The manual arc welding set-up in Figure 2 has a heat-transfer factor of 0.8 and a melting factor of 0.5; the unit energy to melt the metal is 10 J/mm^{3}. Determine (a) the heat input to the work per unit length of weld (answer in J/mm) and (b) the cross-sectional area of the weld bead (answer in mm^{2}).