Heated air at 1 atm and 25°c is to be transported in a 250 m long circular duct at a rate of 0.45 m/s. if the head loss in the pipe is not to exceed 20m, determine the minimum diameter of the duct.

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?