Consider a 1000-w iron whose base plate is made of 0.5-cm-thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp= 875 j/kg-°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90 percent of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.