One cubic foot of air at 15 psia and 600 r is compressed reversibly at constant volume to 90 psia. determine the change in total internal energy of the air (btu).

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

Asteel wire of 2 mm diameter is fixed between two points located 2 m apart. the tensile force in the wire is 250n, if its density of steel is given by 7830 kg/m3 the fundamental frequency of vibration hz? ?

Determine (a) the maximum thermal efficiency of reversible power cycles operating between a hot reservoir at 1000°c and a cold reservoir at 200°c and (b) the maximum cops for reversible refrigeration and heat pump cycies, respectively, between 28°c and 14°c.