A hair dryer is basically a duct in which a few layers of electric resistors are placed. A small fan pulls the air in and forces it to flow over the resistors where it is heated. Air enters a 900-W hair dryer at 100 kPa and 25°C, and leaves at 50°C. The cross-sectional area of the hair dryer at the exit is 60 cm². Neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine

(a) The volume flow rate of air at the inlet

(b) The velocity of the air at the exit.

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T2 = 50°C A; = 60 cm2 W, = 900 W = P = 100 kPa T = 25°C