Consider a sphere with a diameter of 20 mm and a surface temperature of 60°c that is immersed in a fluid at a temperature of 30°c and a velocity of 2.5 m/s. calculate the heat rate when the fluid is

(a) water and
(b) air at atmospheric pressure.
explain why the results for the two fluids are so different.

Fluids at rest possess no flow energy. 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?