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a hair dryer is basically a duct in which a few layers of electric resistors are placed. a small fan pulls the air and forces it through the resistors where it is heated. air enters a 1200W hair dryer with a density of 1.19kg/m^3. the rise in internal energy is 17.96kj/kg. the cross sectional area of hair dryer at the exit is 60 cm^2. neglecting the power consumed by the fan and heat losses through the walls of the hair dryer. determine (a) volume flow rate air at the inlet (b) velocity of air at the exit