In a laser cutting process of aluminum plates of 1mm thick, a through hole is to be drilled, followed by melting-dominated cutting. If the focused laser beam is 0.25 mm in diameter (assuming it is the same of the cut width w), a) In order to drill a hole through the plate in 1 ms, determine the laser power required. In the cutting, the laser power is adjusted to be 1,500W. Determine the cutting velocity V achievable. b) For aluminum, p= 2,700 kg/m, L-397 kJ/kg, L, -9,492 kJ/kg. Cp=900 J/kgC, Tm = 660C, T, 2,450C. Assume T, 20C and n = 0.6.