(I) Super InvarTM, an alloy of iron and nickel, is a strong material with a very low coefficient of thermal expansion (0.20 x 10-/C°). A 1.8-m-long tabletop made of this alloy is used for sensitive laser measurements where extremely high tolerances are required. How much will this alloy table expand along its length if the temperature increases 6.0 C°? Compare to tabletops made of steel.

(b) A unidirectional graphite/epoxy bar of reference length 0.25 m and cross sectional area A=300x10-6 m², has been cured in an autoclave at 180 °C. The volume fraction of the fibre is V;=0.55. The fibre has properties Ef=280×10° N/m?, af=-1x10-6/°C. The epoxy matrix has properties Em=3.0x10º N/m2, am =50×10-6 /°C. (i) At an ambient temperature of 30 °C, what is the overall strain in the bar? (ii) What is the resulting stress in the fibre? (iii) At the same ambient temperature, what tensile load on the bar would result in zero stress in the fibre?

A sauna has 8.5 m3 of air volume, and the temperature is85°C. The air is perfectly dry. How much water (in kg)should be evaporated if we want to increase the relativehumidity from 0% to 10%? (See Table 13–3.)