The seasons are caused by varying length of the day light time, which is a result of the tilt of earth's axis relative to the direction perpendicular to the ecliptic. a. the the varying angle at which the sun's rays strike earth, a result of the tilt of earth's axis relative to the direction perpendicular to the ccliptic. b. the changing sun-earth distance, which is a result of the ellipticity of earth's orbit. d. a and b

Ahair 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 through the resistors where it is heated. air enters a 1200 w hair dryer at 100 kpa and 22°c and leaves at 47°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 and (b) the velocity of the air at the exit.