Considere un colector solar de aire que tiene 1 m de ancho y 5 m de largo y un espaciamiento constante de 3 cm entre la cubierta de vidrio y la placa del propio colector. El aire entra en el colector a 30°C a razón de 0.15m3 /s por el borde de 1 m de ancho y fluye a lo largo del paso de 5 m de largo. Si las temperaturas promedio de la cubierta de vidrio y de la placa del colector son de 20°C y 60°C, respectivamente, determine a) la razón neta de la transferencia de calor hacia el aire conforme fluye por el colector y b) la elevación de temperatura del aire conforme fluye a través del colector.

The force on a cutting tool are 2600n vertically downward and 2100 horizontal. determine the resultant force acting on the tool and the angle at which it acts.

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.

For a gate width of 2 m into the paper, determine the force required to hold the gate abc at its location.