Based on the following chart, what material has the least overall embodied energy? Material Energy (megajoules per kilogram of building material) kg of CO2 per kg (kilograms of carbon dioxide per kilogram of building material)
aluminum 155 8.24
bricks 3.00 0.24
concrete 1.11 0.159
lumber 8.5 0.46
steel 20.1 1.37

lumber

concrete

steel

aluminum

bricks

If you were designing a bumper for a car, would you prefer it to exhibit elastic or plastic deformation? why? consider the functions of a bumper in both a minor "fender-bender" and a major collision.

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?