250mm diameter solid shaft is used to drive the propeller of a marine vessel. It is necessaryto reduce the weight if the shaft by 70%. What would be the dimension of a hollow shaft madeof the same materials as the solid shaft

Water vapor initially at 10 bar and 400 °c is contained within a piston-cylinder assembly. the water lost heat to the surrounding according to isochoric (iso-volumetric) process until its temperature is 150 °c. the water is then condensed isothermally to saturated liquid. for the water as a system, calculate the work in kj/kg