A gas tungsten arc-welding is performed to join two aluminium workpieces through continuous fillet welding. The current and voltage of the arc-welding operation is 300A and 20V, respectively. The travel speed of electrode is 10.5 mm/s. The cross-section area of the weldment (perpendicular to the travel direction) is 20 mm². The unit melting energy for the metal workpiece is 10 J/mm³ and the melting factor is 0.5. Determine (a) the volume rate of metal welded; (b) the rate of heat delivered to the welding operation; (c) the rate of input energy generated by the welding power source (d) The heat transfer factor of this arc-welding operation.