Based on the following passage, which of the following would be an example of a sustainable input for the construction industry? Advocates for sustainable construction acknowledge that the planet’s built environment is the largest single contributor to pollution and ecosystem destruction in the world—larger even than the pollution caused by the internal combustion engine. The built environment relies on inputs of land, water use, raw materials, and energy. Its outputs include water pollution, solid waste, and carbon emissions.

A. hemp and straw

B. cold-formed steel

C. gray water

D. old-growth wood

Tom is having a problem with his washing machine. he notices that the machine vibrates violently at a frequency of 1500 rpm due to an unknown rotating unbalance. the machine is mounted on 4 springs each having a stiffness of 10 kn/m. tom wishes to add an undamped vibration absorber attached by a spring under the machine the machine working frequency ranges between 800 rpm to 2000 rpm and its total mass while loaded is assumed to be 80 kg a) what should be the mass of the absorber added to the machine so that the natural frequency falls outside the working range? b) after a first trial of an absorber using a mass of 35 kg, the amplitude of the oscillation was found to be 10 cm. what is the value of the rotating unbalance? c) using me-3.5 kg.m, find the optimal absorber (by minimizing its mass). what would be the amplitude of the oscillation of the absorber?